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A275255 G.f.: A(x) = x*Product_{n>=1} (1+a(n)^2*x^n) = Sum_{n>=1} a(n)*x^n. 0
1, 1, 1, 2, 5, 30, 930, 865833, 749667649743, 562001585071942995616767, 315845781623376380137718569771289227717728016656 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
LINKS
FORMULA
G.f.: A(x) = x*Product_{n>=1} (1+a(n)^2*x^n) = Sum_{n>=1} a(n)*x^n.
EXAMPLE
a(1)=a(2)=a(3)=1.
a(4)=a(1)^2*a(2)^2+a(3)^2=2.
a(5)=a(1)^2*a(3)^2+a(4)^2=5.
MATHEMATICA
num = 10; g = Table[1, {n, 1, num}]; g[[1]] = Table[1, {n, 1, num}];
For[i = 2, i <= num, i++, g[[i]] = Table[CoefficientList[Series[Product[(1 + g[[i - 1]][[k]]^2 x^k), {k, 1, num}], {x, 0, num}], x][[n]], {n, 1, num}]; ]; g[[num]]
CROSSREFS
Cf. A032305 for a similar g.f. property.
Sequence in context: A369726 A129951 A127298 * A219273 A000133 A059086
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified March 2 09:28 EST 2024. Contains 370461 sequences. (Running on oeis4.)