A136229 Column 1 of triangle A136228; also equals column 3 of square array A136217.

1, 4, 24, 198, 2116, 28052, 446560, 8325700, 178284892, 4317391240, 116757568072, 3489919886180, 114304360656596, 4072431454706374, 156845310426959972, 6494800764749659199, 287796117221639178946, 13590112496057829388516

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Prog

(PARI) {a(n)=local(P=Mat(1), U=Mat([1, 0; 1, 1]), PShR); if(n>0, for(i=0, n+1, PShR=matrix(#P, #P, r, c, if(r>=c, if(r==c, 1, if(c==1, 0, P[r-1, c-1])))); U=P*PShR^2; U=matrix(#P+1, #P+1, r, c, if(r>=c, if(r<#P+1, U[r, c], if(c==1, (P^3)[ #P, 1], (P^(3*c-1))[r-c+1, 1])))); P=matrix(#U, #U, r, c, if(r>=c, if(r<#R, P[r, c], (U^c)[r-c+1, 1]))))); U[n+2, 2]}

Crossrefs

Cf. A136228, A136217; A136221.

Sequence in context: A362355 A099021 A220690 * A138419 A366341 A341727

Adjacent sequences: A136226 A136227 A136228 * A136230 A136231 A136232

Keyword

nonn

Author

Paul D. Hanna, Jan 28 2008

Status

approved