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Search: id:A104448
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| 1, 3, 6, 13, 33, 101, 372, 1624, 8263, 48285, 320031, 2380114, 19675986, 179314868, 1788473424, 19398149629, 227510745445, 2871040422932, 38810001746171, 559745948482030, 8582882169611759, 139467832061599433
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OFFSET
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0,2
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COMMENT
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A104446 equals the square of triangular matrix A104445, read by rows, where X=[A104445] satisfies: SHIFT_LEFT_UP(X) = X^2 - X + I.
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FORMULA
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a(n) = A091352(n) + A091352(n-1) for n>0.
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PROGRAM
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(PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+1, B=A^2-A+A^0; A=matrix(m+1, m+1); for(i=1, m+1, for(j=1, i, if(i<2|j==i, A[i, j]=1, if(j==1, A[i, j]=1, A[i, j]=B[i-1, j-1]))))); return(sum(k=1, n+1, (A^2)[n+1, k]))}
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CROSSREFS
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Cf. A104446, A104445, A091352, A091351.
Sequence in context: A018014 A162483 A026538 this_sequence A062466 A053564 A036781
Adjacent sequences: A104445 A104446 A104447 this_sequence A104449 A104450 A104451
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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), Mar 08 2005
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