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A143564 G.f. satisfies: A(x) = 1 + x*A(x)^4/A(-x)^3. 1
1, 1, 7, 31, 273, 1697, 16471, 116159, 1186081, 8928193, 94017703, 736522975, 7917810225, 63722594657, 695248655095, 5705316231551, 62944217175617, 524183926274433, 5833380674885959, 49141433498848159, 550674827214221137 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
G.f. satisfies: A(x) + A(-x) = 1 + (1+x^2)*A(x)*A(-x).
G.f.: A(x) = G(x)/(1+x^2) where G(x) = 1 + x*G(x)^4/G(-x)^4 is the g.f. of A143557.
EXAMPLE
G.f. A(x) = 1 + x + 7*x^2 + 31*x^3 + 273*x^4 + 1697*x^5 +...
A(x)*A(-x) = 1 + 13*x^2 + 533*x^4 + 32409*x^6 + 2339753*x^8 +...
PROG
(PARI) {a(n)=local(A=1+x*O(x^n)); for(i=0, n, A=1+x*A^4/subst(A^3, x, -x)); polcoeff(A, n)}
CROSSREFS
Sequence in context: A094711 A333735 A221875 * A352411 A344787 A253596
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 24 2008
STATUS
approved

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)