cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A349033 G.f. A(x) satisfies: A(x) = 1 / (1 - x - x * A(-3*x)).

Original entry on oeis.org

1, 2, -2, -34, 826, 70634, -16895162, -12385295242, 27037369868722, 177500531682526034, -3493033395457140741746, -206274103942288894158940594, 36540013650535335202759969693162, 19419007557809179132528500713950083002, -30960092711143410415029705970483650552421802
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 06 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 14; A[] = 0; Do[A[x] = 1/(1 - x - x A[-3 x]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
    a[0] = 1; a[n_] := a[n] = a[n - 1] + Sum[(-3)^k a[k] a[n - k - 1], {k, 0, n - 1}]; Table[a[n], {n, 0, 14}]

Formula

a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} (-3)^k * a(k) * a(n-k-1).

A349034 G.f. A(x) satisfies: A(x) = 1 / (1 - x - x * A(-4*x)).

Original entry on oeis.org

1, 2, -4, -88, 5360, 1395104, -1423111744, -5834786588032, 95573832673124096, 6263909110244685920768, -1642021136070472933898232832, -1721790522986063937046243536001024, 7221705990593287793620261453916626546688, 121160150179535955805047509278599956409746825216
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 06 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 13; A[] = 0; Do[A[x] = 1/(1 - x - x A[-4 x]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
    a[0] = 1; a[n_] := a[n] = a[n - 1] + Sum[(-4)^k a[k] a[n - k - 1], {k, 0, n - 1}]; Table[a[n], {n, 0, 13}]

Formula

a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} (-4)^k * a(k) * a(n-k-1).
Showing 1-2 of 2 results.