jackwener/OpenCLI · warning · EmptyResultError
oeis sequence
oeis sequence
Error message
OEIS sequence "${id}" not found. What it means
An EmptyResultError with code "oeis sequence" thrown when the id-based OEIS lookup (search?q=id:A<n>&fmt=json) returns an empty array, meaning OEIS has no sequence with that A-number. The id passed requireSequenceId validation, so it is well-formed but unknown.
Source
Thrown at clis/oeis/sequence.js:48
'termCount',
'offset',
'author',
'created',
'revision',
'commentCount',
'formulaCount',
'referenceCount',
'xrefCount',
'linkCount',
'url',
],
func: async (args) => {
const id = requireSequenceId(args.id);
const url = `${OEIS_BASE}/search?q=id:${encodeURIComponent(id)}&fmt=json`;
const body = await oeisFetch(url, 'oeis sequence');
const list = Array.isArray(body) ? body : [];
if (!list.length) {
throw new EmptyResultError('oeis sequence', `OEIS sequence "${id}" not found.`);
}
const r = list[0];
const data = typeof r?.data === 'string' ? r.data : '';
const termCount = data ? data.split(',').filter(Boolean).length : 0;
return [{
id: formatId(r?.number) ?? id,
name: typeof r?.name === 'string' ? r.name : null,
keywords: typeof r?.keyword === 'string' ? r.keyword : null,
preview: previewTerms(data),
termCount,
offset: typeof r?.offset === 'string' ? r.offset : null,
author: typeof r?.author === 'string' ? r.author : null,
created: typeof r?.created === 'string' ? r.created : null,
revision: typeof r?.revision === 'number' ? r.revision : null,
commentCount: asArray(r?.comment).length,
formulaCount: asArray(r?.formula).length,
referenceCount: asArray(r?.reference).length,
xrefCount: asArray(r?.xref).length,View on GitHub (pinned to 49907e53dc)
Solutions
- Verify the A-number on oeis.org directly (oeis.org/A000045).
- Use oeis search with the sequence terms instead of the id to recover the correct id.
- Check for digit transposition in the id you typed.
- Confirm the entry still exists — OEIS occasionally renumbers or merges sequences.
Example fix
// before oeis sequence A0000046 // after (Fibonacci) oeis sequence A000045
Defensive patterns
Strategy: fallback
Validate before calling
const SEQ_ID = /^A\d{1,7}$/;
if (!SEQ_ID.test(String(raw ?? '').trim())) throw new Error('bad A-number'); Type guard
const isSeqId = (v) => /^A\d{1,7}$/.test(String(v ?? '').trim()); Try / catch
try { return await oeisSequence(id); } catch (e) { if (e.code === 'oeis sequence') return null; throw e; } Prevention
- Verify A-numbers on oeis.org before scripted use.
- Fall back to a term-based search when an id lookup comes up empty.
- Watch for digit transposition when transcribing ids.
- Don't assume OEIS ids are contiguous or permanent.
When it happens
Trigger: Requesting a well-formed but non-existent A-number (e.g. A9999999), a mistyped digit in a valid id, or referencing an id from a stale cache/link pointing at a renumbered/removed entry.
Common situations: Typos when transcribing A-numbers from papers or logs, assuming ids are contiguous, or using fabricated ids in generated test data.
Understand the failure class
Background: Record Not Found Errors: "not found", RecordNotFound, and "was not found" — what they mean and how to fix them — this error's family across 28 libraries.
Related errors
AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29).
Data as JSON: /api/errors/dc28e17349cb0f74.
Report an issue: GitHub.