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A176720
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G.f. satisfies: A(x) = 1 + Sum_{n>=0} 2*x^(n^2)*A(x)^n.
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1
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1, 2, 4, 8, 18, 44, 112, 288, 744, 1938, 5104, 13584, 36456, 98468, 267376, 729488, 1999074, 5500412, 15189636, 42084952, 116949848, 325878288, 910333152, 2548892864, 7152113760, 20108587038, 56641227416, 159820928328
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OFFSET
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0,2
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LINKS
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EXAMPLE
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G.f.: A(x) = 1 + 2*x + 4*x^2 + 8*x^3 + 18*x^4 + 44*x^5 + 112*x^6 +...
A(x) = 1 + 2*x*A(x) + 2*x^4*A(x)^2 + 2*x^9*A(x)^3 + 2*x^16*A(x)^4 + ...
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PROG
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(PARI) {a(n)=local(A=1+x); for(i=1, n, A=1+sum(m=1, n, 2*(A+x*O(x^n))^m*x^(m^2))); 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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EXTENSIONS
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STATUS
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approved
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