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Search: id:A121418
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| 1, 2, 7, 43, 403, 5188, 85569, 1725291, 41145705, 1133047596, 35377360292, 1234796503280, 47636225803285, 2012509471127885, 92398547122062997, 4580472438441602301, 243822925502110419105, 13870297863425823346284
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OFFSET
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0,2
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COMMENT
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Also column 1 of square array A136733.
A121416 is the matrix square of triangle A121412; row n of triangle T=A121412 equals row (n-1) of T^(n+1) with an appended '1'.
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PROGRAM
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(PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+1, 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^2)[n+1, 1])}
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CROSSREFS
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Cf. A121416 (triangle); other columns: A121418, A121419.
Cf. A136733; A101483, A121421; A121425.
Sequence in context: A144059 A078676 A086331 this_sequence A014501 A011835 A103084
Adjacent sequences: A121415 A121416 A121417 this_sequence A121419 A121420 A121421
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Aug 22 2006, Jan 19 2008
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Oct 30 2008 at the suggestion of R. J. Mathar
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