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A121422 Column 1 of triangle A121420. 11
1, 3, 15, 118, 1317, 19311, 352636, 7722840, 197354133, 5764942816, 189460961985, 6917588290044, 277765971072770, 12163275845132298, 576793897136731632, 29444368084753254610, 1609805318425385690712, 93843785859803533422675 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Also column 2 of square array A136737.
A121420 is the matrix cube of triangle A121412; row n of triangle T=A121412 equals row (n-1) of T^(n+1) with an appended '1'.
LINKS
PROG
(PARI) {a(n)=local(A=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]=(A^i)[i-1, j]); )); A=B); return((A^3)[n+2, 2])}
CROSSREFS
Cf. A121420 (triangle); other columns: A121421, A121423.
Sequence in context: A136654 A364621 A145161 * A060639 A068052 A068859
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 23 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 February 26 10:03 EST 2024. Contains 370340 sequences. (Running on oeis4.)