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.

A384859 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of e.g.f. B(x)^k, where B(x) is the e.g.f. of A384855.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 7, 0, 1, 3, 16, 10, 0, 1, 4, 27, 62, -503, 0, 1, 5, 40, 162, -632, -8564, 0, 1, 6, 55, 316, -135, -20758, -103751, 0, 1, 7, 72, 530, 1264, -31572, -413900, 3479554, 0, 1, 8, 91, 810, 3865, -34316, -919647, 2636678, 327940225, 0, 1, 9, 112, 1162, 7992, -20500, -1552472, -5475222, 679001872, 8613464536, 0
Offset: 0

Views

Author

Seiichi Manyama, Jun 10 2025

Keywords

Examples

			Square array begins:
  1,     1,      1,      1,      1,      1, ...
  0,     1,      2,      3,      4,      5, ...
  0,     7,     16,     27,     40,     55, ...
  0,    10,     62,    162,    316,    530, ...
  0,  -503,   -632,   -135,   1264,   3865, ...
  0, -8564, -20758, -31572, -34316, -20500, ...
		

Crossrefs

Columns k=0..1 give A000007, A384855.

Programs

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

Formula

Let b(n,k) = 0^n if n*k=0, otherwise b(n,k) = (-1)^n * k * Sum_{j=1..n} (-n+j+k)^(j-1) * binomial(n,j) * b(n-j,3*j). Then A(n,k) = b(n,-k).

A384856 E.g.f. A(x) satisfies A(x) = exp( x/A(-x*A(x)^2)^3 ).

Original entry on oeis.org

1, 1, 7, 28, -107, -11744, -519101, -12366080, -101065751, 19899785728, 2369020104991, 160985802059776, 8664193820140093, 137309806362677248, -48557247646714851365, -9196626471351773732864, -1230646715294157585659951, -124354471985557029636669440, -8657982884640209349171498569
Offset: 0

Views

Author

Seiichi Manyama, Jun 10 2025

Keywords

Crossrefs

Programs

  • PARI
    a(n, k=-1) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, (-2*n+2*j+k)^(j-1)*binomial(n, j)*a(n-j, 3*j)));

Formula

See A384860.

A384857 E.g.f. A(x) satisfies A(x) = exp( x/A(-x*A(x)^3)^3 ).

Original entry on oeis.org

1, 1, 7, 46, 361, -6284, -632951, -31583474, -1484748191, -51928436312, -303653774159, 219248741052826, 35743757192135425, 4097960104621191004, 408462300514973323753, 33384541884258873033406, 1521231207001104466842049, -200132739000502301652035888, -84772475888572203988197350303
Offset: 0

Views

Author

Seiichi Manyama, Jun 10 2025

Keywords

Crossrefs

Programs

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

Formula

See A384861.

A384858 E.g.f. A(x) satisfies A(x) = exp( x/A(-x*A(x)^8)^3 ).

Original entry on oeis.org

1, 1, 7, 136, 3781, 163216, 9103699, 646696576, 55084545289, 5491386074368, 625131329307391, 79898089652402176, 11312691034562944525, 1755128489880477528064, 295767148537661982373963, 53734366029378178883731456, 10459045695948264117117132049, 2169330513346145105101803814912
Offset: 0

Views

Author

Seiichi Manyama, Jun 10 2025

Keywords

Crossrefs

Programs

  • PARI
    a(n, k=-1) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, (-8*n+8*j+k)^(j-1)*binomial(n, j)*a(n-j, 3*j)));

Formula

See A384862.
Showing 1-4 of 4 results.