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.

A090367 Shifts 1 place left under the INVERT transform of the BINOMIAL transform of the self-convolution cube of this sequence.

Original entry on oeis.org

1, 1, 5, 34, 276, 2509, 24739, 259815, 2873376, 33207790, 398897289, 4960652325, 63676368387, 841741913795, 11438028248093, 159536511439266, 2281321298635427, 33411684617642665, 500761214428795093, 7674842860939188928, 120209960716130232745
Offset: 0

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Author

Paul D. Hanna, Nov 26 2003

Keywords

Crossrefs

Programs

  • Maple
    bintr:= proc(p) local b; b:= proc(n) option remember;
               add(p(k) *binomial(n,k), k=0..n) end
            end:
    invtr:= proc(p) local b; b:= proc(n) option remember;
               `if`(n<1, 1, add(b(n-i) *p(i-1), i=1..n+1)) end
            end:
    s:= proc(n) option remember; add(a(i)*a(n-i), i=0..n) end:
    b:= invtr(bintr(n-> add(s(i)*a(n-i), i=0..n))):
    a:= n-> `if`(n<0, 0, b(n-1)):
    seq(a(n), n=0..25);  # Alois P. Heinz, Jun 28 2012
  • Mathematica
    m = 25; A[] = 1; Do[A[x] = 1/(1 - A[x/(1-x)]^3*(x/(1-x))) + O[x]^m // Normal, {m}]; CoefficientList[A[x], x] (* Jean-François Alcover, Jun 04 2018 *)
  • PARI
    {a(n)=local(A); if(n<0,0,A=1+x+x*O(x^n); for(k=1,n,B=subst(A^3,x,x/(1-x))/(1-x)+x*O(x^n); A=1+x*A*B);polcoeff(A,n,x))}

Formula

G.f.: A(x) = 1/(1 - A(x/(1-x))^3*x/(1-x) ).