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 1-3 of 3 results.

A384362 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where A(n,k) = Sum_{i=0..k*n} 2^i * Sum_{j=0..i} (-1)^j * binomial(i,j) * binomial(i-j,n)^k.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 10, 4, 1, 1, 74, 148, 8, 1, 1, 730, 13540, 2440, 16, 1, 1, 9002, 2308756, 3087368, 42256, 32, 1, 1, 133210, 632363044, 10208479240, 778026256, 752800, 64, 1, 1, 2299754, 253970683348, 69754997963528, 52520969994256, 207633589664, 13660480, 128, 1
Offset: 0

Views

Author

Seiichi Manyama, May 27 2025

Keywords

Examples

			Square array begins:
  1,  1,     1,         1,              1, ...
  1,  2,    10,        74,            730, ...
  1,  4,   148,     13540,        2308756, ...
  1,  8,  2440,   3087368,    10208479240, ...
  1, 16, 42256, 778026256, 52520969994256, ...
		

Crossrefs

Columns k=0..2 give A000012, A000079, A098270.
Rows n=0..1 give A000012, A004123(k+1).

Programs

  • PARI
    a(n, k) = sum(i=0, k*n, 2^i*sum(j=0, i, (-1)^j*binomial(i, j)*binomial(i-j, n)^k));

Formula

A(n,k) = (1/3) * Sum_{j>=0} (2/3)^j * binomial(j,n)^k.

A384359 Expansion of Product_{k>=1} 1/(1 - k*(k+1)/2 * x)^((1/48) * (3/4)^k).

Original entry on oeis.org

1, 1, 37, 4453, 1126375, 489185863, 324848377243, 306044183298331, 388203452145317314, 637855747987693348770, 1317841032827800659419754, 3343784211346797764798294634, 10221662989279986155378379955158, 37051850653048390530321630384383382, 157140052593846256021318451838028238910
Offset: 0

Views

Author

Seiichi Manyama, May 27 2025

Keywords

Crossrefs

Cf. A384364.

Programs

  • PARI
    a384364(n, k) = sum(i=0, k*n, 3^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, a384364(2, k)*x^k/k)/9))

Formula

G.f.: exp((1/9) * Sum_{k>=1} A384364(2,k) * x^k/k).

A384360 Expansion of Product_{k>=1} 1/(1 - k*(k+1)*(k+2)/6 * x)^((1/192) * (3/4)^k).

Original entry on oeis.org

1, 1, 424, 998584, 6925040260, 105920615923684, 3026129933925315784, 144928319460945421096936, 10782220800085014574469693026, 1177609713750570874317795178806210, 180749886489278186545417627942230436008, 37658177020555445685152123914054243838809128
Offset: 0

Views

Author

Seiichi Manyama, May 27 2025

Keywords

Crossrefs

Cf. A384364.

Programs

  • PARI
    a384364(n, k) = sum(i=0, k*n, 3^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, a384364(3, k)*x^k/k)/27))

Formula

G.f.: exp((1/27) * Sum_{k>=1} A384364(3,k) * x^k/k).
Showing 1-3 of 3 results.