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.

A059373 Second diagonal of triangle in A059370.

Original entry on oeis.org

1, -4, 8, -16, 12, -96, -480, -4672, -45520, -493120, -5798912, -73668608, -1005335552, -14671085568, -228051746304, -3762955404288, -65707303602432, -1210821292674048, -23487031074109440, -478463919131627520, -10214440549929047040, -228069193578011566080
Offset: 2

Views

Author

N. J. A. Sloane, Jan 28 2001

Keywords

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 171, #34.

Crossrefs

Cf. A059370.

Programs

  • Maple
    series(RootOf(T*hypergeom([1,2],[],T)-x,T)^2,x=0,21); # Mark van Hoeij, Apr 20 2013
  • Mathematica
    nmax = 23; t[n_, k_] := t[n, k] = Sum[(m+1)!*t[n-m-1, k-1], {m, 0, n-k}]; t[n_, 1] = n!; t[n_, n_] = 1; tnk = Table[t[n, k], {n, 1, nmax}, {k, 1, nmax}]; A059370 = Reverse /@ Inverse[tnk] // DeleteCases[#, 0, 2] & ; Table[A059370[[n, n - 1]], {n, 2, nmax}] (* Jean-François Alcover, Jun 14 2013 *)
  • PARI
    N = 66;  x = 'x + O('x^N);
    tf = sum(n=1,N, n!*x^n );
    gf=serreverse(%)^2;
    v = Vec(gf)
    /* Joerg Arndt, Apr 20 2013 */

Formula

G.f. A(x) is (R(x))^2 where R(x) is the series reversion of x*hypergeom([1,2],[],x) = sum(n>=1, n!*x^n), see Comtet. - Mark van Hoeij, Apr 20 2013

Extensions

Added more terms, Mark van Hoeij and Joerg Arndt, Apr 20 2013

A059369 Triangle of numbers T(n,k) = T(n-1,k-1) + ((n+k-1)/k)*T(n-1,k), n >= 1, 1 <= k <= n, with T(n,1) = n!, T(n,n) = 1; read from right to left.

Original entry on oeis.org

1, 1, 2, 1, 4, 6, 1, 6, 16, 24, 1, 8, 30, 72, 120, 1, 10, 48, 152, 372, 720, 1, 12, 70, 272, 828, 2208, 5040, 1, 14, 96, 440, 1576, 4968, 14976, 40320, 1, 16, 126, 664, 2720, 9696, 33192, 115200, 362880, 1, 18, 160, 952, 4380, 17312, 64704, 247968, 996480
Offset: 1

Views

Author

N. J. A. Sloane, Jan 28 2001

Keywords

Comments

Another version of triangle in A090238. - Philippe Deléham, Jun 14 2007

Examples

			When read from left to right the rows {T(n,k), 1 <= k <= n} for n=1,2,3,... are 1; 2,1; 6,4,1; 24,16,6,1; ...
		

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 171, #34.

Crossrefs

Programs

  • Mathematica
    nmax = 10; t[n_, k_] := Sum[(m+1)!*t[n-m-1, k-1], {m, 0, n-k}]; t[n_, 1] = n!; t[n_, n_] = 1; Flatten[ Table[ t[n, k], {n, 1, nmax}, {k, n, 1, -1}]] (* Jean-François Alcover, Nov 14 2011 *)

Formula

G.f. for k-th diagonal: (Sum_{i >= 1} i!*t^i)^k = Sum_{n >= k} T(n, k)*t^n.
T(n,k) = n! if k=1, 1 if k=n, Sum_{m=0..n-k} (m+1)!*T(n-m-1,k-1) otherwise. - Vladimir Kruchinin, Aug 18 2010

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jan 31 2001

A059372 Revert transform of factorials n! (n >= 1).

Original entry on oeis.org

1, -2, 2, -4, -4, -48, -336, -2928, -28144, -298528, -3454432, -43286528, -583835648, -8433987584, -129941213184, -2127349165824, -36889047574272, -675548628690432, -13030733384956416, -264111424634864640
Offset: 1

Views

Author

N. J. A. Sloane, Jan 28 2001

Keywords

Comments

First diagonal of triangle in A059370.

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 171, #34.

Crossrefs

Programs

  • Maple
    # From Transforms, see the footer of the page.
    REVERT([seq(k!, k=1..20)]); # Peter Luschny, May 01 2021
    # Using function CompInv from A357588.
    CompInv(10, n -> factorial(n)); # Peter Luschny, Oct 09 2022
  • Mathematica
    nmax = 20; t[n_, k_] := t[n, k] = Sum[(m + 1)!*t[n - m - 1, k - 1], {m, 0, n - k}]; t[n_, 1] = n!; t[n_, n_] = 1; tnk = Table[t[n, k], {n, 1, nmax}, {k, 1, nmax}]; Inverse[tnk][[All, 1]] (* Jean-François Alcover, Jul 13 2016 *)

Formula

a(n) ~ -exp(-2) * n! * (1 - 4/n + 2/n^2 - 34/(3*n^3) - 296/(3*n^4) - 4818/(5*n^5) - 508532/(45*n^6)). - Vaclav Kotesovec, Aug 04 2015
G.f. A(x) satisfies: A(x) = x - Sum_{k>=2} k! * A(x)^k. - Ilya Gutkovskiy, Apr 22 2020

Extensions

More terms from Vladeta Jovovic, Mar 05 2001
Definition refined by Georg Fischer, May 01 2021
Showing 1-3 of 3 results.