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Search: id:A128571
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| 1, 2, 12, 114, 1440, 22368, 409248, 8585088, 202733760, 5317663680, 153345634560, 4821848409600, 164211751261440, 6022162697840640, 236652023784960000, 9921992082873223680, 442138176056374548480, 20869300232695599552000
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OFFSET
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0,2
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FORMULA
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G.f.: A(x) = 1 + 2x*R(x,2)^2, where R(x,2) = 1 + 3*x*R(x,3)^2, R(x,3) = 1 + 4*x*R(x,4)^2, ..., R(x,n) = 1 + (n+1)*x*R(x,n+1)^2, ... and R(x,n) is the g.f. of row n of table A128570.
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PROGRAM
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(PARI) {a(n)=local(A=1+(n+2)*x); for(j=0, n, A=1+(n+2-j)*x*A^2 +x*O(x^n)); polcoeff(A, n)}
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CROSSREFS
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Cf. A128570 (triangle), other rows: A128318, A128572, A128573, A128574, A128575, A128576; A128577 (square of row 0), A128578 (main diagonal), A128579 (antidiagonal sums).
Sequence in context: A053312 A091854 A141141 this_sequence A052696 A107723 A035051
Adjacent sequences: A128568 A128569 A128570 this_sequence A128572 A128573 A128574
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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 11 2007
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