A173223 Column 2 of triangle A173220.

0, 12, 90, 4320, 418950, 68045040, 16408798560, 5461729378560, 2388307104414000, 1323740028257460000, 905000067758493495360, 747005694270473162004480, 731648558087385682524580800

Offset

0,2

Comments

Triangle A173220 is the matrix log of triangle T = A173210, which satisfies: row n of T^n = row n of (I+D)^(n^2) where D is the lower diagonal matrix: D(n+1,n)=n+1.

Links

Table of n, a(n) for n=0..12.

Prog

(PARI) {a(n)=local(M=Mat(1), N, L=Mat(1), C=matrix(n+4, n+4, r, c, if(r==c, 1, if(r==c+1, c)))); for(i=1, n+3, N=M; M=matrix(#N+1, #N+1, r, c, if(r>=c, if(r<=#N, (N^(#N))[r, c], (C^((#M)^2))[r, c]))); L=sum(i=1, #M, -(M^0-M)^i/i); M=sum(i=0, #M, (L/#N)^i/i!); ); L[n+3, 3]/(n+2)}

Crossrefs

Cf. A173220, A173221, A173222, A173224.

Sequence in context: A231512 A250344 A135173 * A114860 A001502 A001503

Adjacent sequences: A173220 A173221 A173222 * A173224 A173225 A173226

Keyword

nonn

Author

Paul D. Hanna, Feb 12 2010

Status

approved