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A121427 Main diagonal of rectangular table A121426. 6
1, 2, 15, 178, 2820, 55410, 1294776, 35003430, 1073540871, 36805249870, 1394346324624, 57831360118800, 2605921998840420, 126757491839620950, 6619466939158637640, 369368127676399990338, 21932876159270004129285 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Also main diagonal of square array A136737.
LINKS
FORMULA
a(n) = [A121412^(n+1)](n+1,1) for n>=0; i.e., (n+1)-th term of column 1 in matrix power A121412^(n+1).
PROG
(PARI) {a(n)=local(H=Mat(1), B); for(m=1, n+2, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, B[i, j]=(H^i)[i-1, j]); )); H=B); return((H^(n+1))[n+2, 2])}
CROSSREFS
Sequence in context: A036080 A215368 A200795 * A364340 A099709 A208409
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 26 2006
EXTENSIONS
Edited by N. J. A. Sloane, Oct 30 2008 at the suggestion of R. J. Mathar
STATUS
approved

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)