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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 Table of n, a(n) for n=0..17. 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. Cf. A136737; A121413, A121417; A121427, A136741. Sequence in context: A136654 A364621 A145161 * A060639 A068052 A068859 Adjacent sequences: A121419 A121420 A121421 * A121423 A121424 A121425 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.)