A129101 Column 1 of triangle A129100; also equals column 0 of the matrix square of A129100.

1, 2, 6, 24, 136, 1162, 15702, 346768, 12836904, 814033666, 90074891654, 17659668432744, 6211830230882472, 3960850942657072026, 4617438765658479411542, 9912250203901899238148640

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Formula

a(n) = A129094(n+1) - A129093(n); a(n) = A030067(2^(n+1)+2^n-1) - A030067(2^(n+1)-3) for n>=0 where A030067 is the semi-Fibonacci numbers.

Prog

(PARI) a(n)=local(A=Mat(1), B); for(m=1, n+2, B=matrix(m, m); for(r=1, m, for(c=1, r, if(r==c || r==1 || r==2, B[r, c]=1, if(c==1, B[r, 1]=sum(i=1, r-1, A[r-1, i]), B[r, c]=(A^(2^(c-1)))[r-c+1, 1])); )); A=B); return(A[n+2, 2])

Crossrefs

Cf. A129100 (triangle); A129092 (column 0), A129102 (column 2), A129103 (column 3).

Sequence in context: A370017 A343482 A216779 * A292907 A216507 A366459

Adjacent sequences: A129098 A129099 A129100 * A129102 A129103 A129104

Keyword

nonn

Author

Paul D. Hanna, Mar 29 2007

Status

approved