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.

A117270 Matrix log of triangle M = A117269, which satisfies: M - (M-I)^2 = C where C is Pascal's triangle.

Original entry on oeis.org

0, 1, 0, 2, 2, 0, 12, 6, 3, 0, 134, 48, 12, 4, 0, 2100, 670, 120, 20, 5, 0, 42302, 12600, 2010, 240, 30, 6, 0, 1041852, 296114, 44100, 4690, 420, 42, 7, 0, 30331814, 8334816, 1184456, 117600, 9380, 672, 56, 8, 0, 1019056260, 272986326, 37506672, 3553368
Offset: 0

Views

Author

Paul D. Hanna, Mar 05 2006

Keywords

Comments

E.g.f. of column 0 (A117271) is log( (3-sqrt(5-4*exp(x)))/2 ) and equals the log of the g.f. of column 0 of A117269.

Examples

			Triangle begins:
0;
1,0;
2,2,0;
12,6,3,0;
134,48,12,4,0;
2100,670,120,20,5,0;
42302,12600,2010,240,30,6,0;
1041852,296114,44100,4690,420,42,7,0; ...
		

Crossrefs

Cf. A117269, A117271 (column 0).

Programs

  • PARI
    {a(n)=local(C=matrix(n+1,n+1,r,c,if(r>=c,binomial(r-1,c-1))),M=C,L); for(i=1,n+1,M=(M-M^0)^2+C);L=sum(r=1,#M,-(M^0-M)^r/r);return(L[n+1,1])}

Formula

T(n,k) = A117271(n-k)*C(n,k).