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1, 2, 12, 108, 1240, 16980, 267624, 4750872, 93615408, 2026018980, 47764893000, 1218621868200, 33459133580496, 983950866169544, 30862364045494800, 1028656519404191280, 36312294166359724128, 1353561646509338629572, 53133041579508472510728
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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G.f. = x + 2*x^2 + 12*x^3 + 108*x^4 + 1240*x^5 + 16980*x^6 + 267624*x^7 + 4750872*x^8 + ...
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PROG
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(PARI) {a(n) = my(A); A = O(x); for(i=1, n, A = x + A * (2 * x * A' - A)); n * polcoeff(A, n)};
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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