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Search: id:A121392
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| A121392 |
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Column 1 of triangle A121391, where column k of T=A121391 equals column k of T^(k+1) shift down 1 row. |
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+0
4
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| 1, 1, 2, 5, 15, 55, 252, 1449, 10305, 88611, 901204, 10642707, 143771206, 2194484737, 37458097842, 708733666387, 14751543118320, 335523928599914, 8290931998724535, 221426442466072303, 6362084485200488267
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Also equal to column 1 (shifted 1 place) of the matrix square of triangle A121391.
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PROGRAM
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(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^j)[i-1, j]); )); A=B); return(A[n+2, 2])}
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CROSSREFS
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Cf. A121391 (triangle), A121393 (column 2), A121394 (column 3).
Sequence in context: A109319 A059219 A137533 this_sequence A119611 A005976 A048192
Adjacent sequences: A121389 A121390 A121391 this_sequence A121393 A121394 A121395
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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), Jul 27 2006
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