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Search: id:A113997
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| 1, 2, 4, 9, 23, 68, 232, 909, 4061, 20538, 116736, 740473, 5206295, 40317216, 341837416, 3156076177, 31572353377, 340658773754, 3948027171748, 48959894881537, 647431703490895, 9100410418912740, 135573816069186800
(list; graph; listen)
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OFFSET
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0,2
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EXAMPLE
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Triangle A113993 begins:
1;
1,1;
1,2,1;
1,4,3,1;
1,8,9,4,1;
1,18,27,16,5,1;
1,46,89,64,25,6,1;
1,136,327,276,125,36,7,1;
1,464,1353,1304,665,216,49,8,1; ...
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PROGRAM
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(PARI) {a(n)=local(A, B); A=Mat(1); for(m=2, n+2, B=matrix(m, m); for(i=1, m, for(j=1, i, if(i<3|j==1|j==i, B[i, j]=1, B[i, j]=A[i-1, j-1]+(A^2)[i-2, j-1] ); )); A=B); sum(k=0, n, (A^(k+1))[n-k+1, 1])}
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CROSSREFS
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Cf. A113993, A113989 (column 1), A113994 (column 2), A113995 (column 3), A113996 (column 4), A113983.
Sequence in context: A026898 A088930 A089844 this_sequence A125789 A058731 A080376
Adjacent sequences: A113994 A113995 A113996 this_sequence A113998 A113999 A114000
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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), Nov 12 2005
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