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.

A384862 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 A384858.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 7, 0, 1, 3, 16, 136, 0, 1, 4, 27, 314, 3781, 0, 1, 5, 40, 540, 8944, 163216, 0, 1, 6, 55, 820, 15741, 383282, 9103699, 0, 1, 7, 72, 1160, 24448, 672768, 21329920, 646696576, 0, 1, 8, 91, 1566, 35365, 1045924, 37392543, 1504825562, 55084545289, 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,    136,    314,    540,     820,    1160, ...
  0,   3781,   8944,  15741,   24448,   35365, ...
  0, 163216, 383282, 672768, 1045924, 1518800, ...
		

Crossrefs

Columns k=0..1 give A000007, A384858.

Programs

  • PARI
    b(n, k) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, (-8*n+8*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} (-8*n+8*j+k)^(j-1) * binomial(n,j) * b(n-j,3*j). Then A(n,k) = b(n,-k).

A384855 E.g.f. A(x) satisfies A(x) = exp( x/A(-x*A(x))^3 ).

Original entry on oeis.org

1, 1, 7, 10, -503, -8564, -103751, 3479554, 327940225, 8613464536, -36391967279, -24834942253274, -2356662167845487, -88482481533921500, 1825569695231959993, 704791058412273699106, 88829364712362626504449, 5460031123686211024338736, 23871425875449192877470625
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, (-n+j+k)^(j-1)*binomial(n, j)*a(n-j, 3*j)));

Formula

See A384859.

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.
Showing 1-4 of 4 results.