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 1-4 of 4 results.

A384364 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where A(n,k) = Sum_{i=0..k*n} 3^i * Sum_{j=0..i} (-1)^j * binomial(i,j) * binomial(i-j,n)^k.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 21, 9, 1, 1, 219, 657, 27, 1, 1, 3045, 119241, 22869, 81, 1, 1, 52923, 40365873, 80850987, 836001, 243, 1, 1, 1103781, 21955523049, 747786838869, 60579666801, 31436181, 729, 1, 1, 26857659, 17512689629457, 14298291269335467, 16117269494868801, 48066954848379, 1204022961, 2187, 1
Offset: 0

Views

Author

Seiichi Manyama, May 27 2025

Keywords

Examples

			Square array begins:
  1,  1,      1,           1,                 1, ...
  1,  3,     21,         219,              3045, ...
  1,  9,    657,      119241,          40365873, ...
  1, 27,  22869,    80850987,      747786838869, ...
  1, 81, 836001, 60579666801, 16117269494868801, ...
		

Crossrefs

Columns k=0..2 give A000012, A000244, 3^n * A084768(n).
Rows n=0..1 give A000012, A032033.

Programs

  • PARI
    a(n, k) = sum(i=0, k*n, 3^i*sum(j=0, i, (-1)^j*binomial(i, j)*binomial(i-j, n)^k));

Formula

A(n,k) = (1/4) * Sum_{j>=0} (3/4)^j * binomial(j,n)^k.

A384356 Expansion of Product_{k>=1} 1/(1 - k*(k+1)/2 * x)^((1/18) * (2/3)^k).

Original entry on oeis.org

1, 1, 19, 1147, 145606, 31784062, 10617130378, 5033441934298, 3213448742033479, 2657684269018334807, 2763967539211567981613, 3530274805575983022456005, 5432490565296371673408076892, 9912854399723224290769677025316, 21163615551469069985356131546443588
Offset: 0

Views

Author

Seiichi Manyama, May 27 2025

Keywords

Crossrefs

Cf. A384362.

Programs

  • PARI
    a384362(n, k) = sum(i=0, k*n, 2^i*sum(j=0, i, (-1)^j*binomial(i, j)*binomial(i-j, n)^k));
    my(N=20, x='x+O('x^N)); Vec(exp(sum(k=1, N, a384362(2, k)*x^k/k)/4))

Formula

G.f.: exp((1/4) * Sum_{k>=1} A384362(2,k) * x^k/k).

A384357 Expansion of Product_{k>=1} 1/(1 - k*(k+1)*(k+2)/6 * x)^((1/54) * (2/3)^k).

Original entry on oeis.org

1, 1, 153, 128793, 319155321, 1744213657689, 17803590830142393, 304609764628470426969, 8095576593110601916260369, 315845539893724747798646514673, 17317064152543324914717101316522961, 1288754843591816442932799782872809777393, 126555732798742295186573610437899751882638209
Offset: 0

Views

Author

Seiichi Manyama, May 27 2025

Keywords

Crossrefs

Cf. A384362.

Programs

  • PARI
    a384362(n, k) = sum(i=0, k*n, 2^i*sum(j=0, i, (-1)^j*binomial(i, j)*binomial(i-j, n)^k));
    my(N=20, x='x+O('x^N)); Vec(exp(sum(k=1, N, a384362(3, k)*x^k/k)/8))

Formula

G.f.: exp((1/8) * Sum_{k>=1} A384362(3,k) * x^k/k).

A384358 Expansion of Product_{k>=1} 1/(1 - k*(k+1)*(k+2)*(k+3)/24 * x)^((1/162) * (2/3)^k).

Original entry on oeis.org

1, 1, 1321, 16210201, 820657237561, 117856012064818489, 38648527065793350391329, 25112088578490906968072202609, 29248901038277816617484354852346429, 56683882435365104654655753669402941927069, 172551008002533192343018045442364399983107657925
Offset: 0

Views

Author

Seiichi Manyama, May 27 2025

Keywords

Crossrefs

Cf. A384362.

Programs

  • PARI
    a384362(n, k) = sum(i=0, k*n, 2^i*sum(j=0, i, (-1)^j*binomial(i, j)*binomial(i-j, n)^k));
    my(N=20, x='x+O('x^N)); Vec(exp(sum(k=1, N, a384362(4, k)*x^k/k)/16))

Formula

G.f.: exp((1/16) * Sum_{k>=1} A384362(4,k) * x^k/k).
Showing 1-4 of 4 results.