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A128329
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Main diagonal of table A128325.
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5
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1, 1, 4, 30, 321, 4389, 72512, 1399755, 30865353, 764755508, 21024535960, 634924059276, 20890221475598, 743727414390456, 28484480606420928, 1167761832049224515, 51022550712426870397, 2366859765773183488674
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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FORMULA
| a(n) = [x^n] {1 + H(x)}, where H(x) is the (n+2)-th self-composition of G(x) and G(x) = x + x*G(G(x)) is the g.f. of A030266.
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PROG
| (PARI) {a(n)=local(A=1+x, B); for(i=0, n, A=1+x*A*subst(A, x, x*A+x*O(x^n))); B=A; for(i=1, n, B=subst(B, x, x*A+x*O(x^n))); polcoeff(B, n)}
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CROSSREFS
| Cf. A030266; A128325 (table), A128326 (row 1), A128327 (row 2), A128328 (row 3).
Sequence in context: A158834 A139086 A180623 * A006149 A121413 A001761
Adjacent sequences: A128326 A128327 A128328 * A128330 A128331 A128332
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KEYWORD
| nonn
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AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), Mar 11 2007
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