A227295 G.f.: ( Sum_{n>=0} 8^n*x^(n^2) )^(1/2).

1, 4, -8, 32, -128, 768, -4608, 28672, -184320, 1212672, -8127488, 55318528, -381329408, 2656845824, -18680250368, 132373807104, -944459216896, 6778991403008, -48915734839296, 354636355665920, -2582006464118784, 18870792427143168, -138396900373037056, 1018196233480568832, -7512565092559355904

Offset

0,2

Links

Table of n, a(n) for n=0..24.

Example

G.f.: A(x) = 1 + 4*x - 8*x^2 + 32*x^3 - 128*x^4 + 768*x^5 - 4608*x^6 +...
where
A(x)^2 = 1 + 8*x + 8^2*x^4 + 8^3*x^9 + 8^4*x^16 + 8^5*x^25 + 8^6*x^36 +...

Prog

(PARI) {a(n)=polcoeff((sum(k=0, n, 8^k*x^(k^2))+x*O(x^n))^(1/2), n)}
for(n=0, 36, print1(a(n), ", "))

Crossrefs

Cf. A227294.

Sequence in context: A252540 A327493 A103970 * A034785 A247938 A072868

Adjacent sequences: A227292 A227293 A227294 * A227296 A227297 A227298

Keyword

sign

Author

Paul D. Hanna, Jul 05 2013

Status

approved