A171801 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A171801

O.g.f.: Sum_{n>=0} (n+1)*2^(n^2)*x^n/(1 - 2^n*x)^n.

1, 4, 56, 2448, 379168, 223096896, 514098000000, 4691436926959872, 170097530401558168064, 24520599890836361905701888, 14055963692387060312500000000000 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,2`
	LINKS	`Table of n, a(n) for n=0..10.`
	FORMULA	`a(n) = 2^n * ((n+1)2^n + 2) (2^n + 1)^(n-2) for n>0 with a(0)=1.`
	EXAMPLE	`G.f.: A(x) = 1 + 4x + 56x^2 + 2448x^3 + 379168x^4 +...` `A(x) = 1 + 22x/(1-2x) + 32^4x^2/(1-2^2x)^2 + 42^9x^3/(1-2^3*x)^3 +...`
	PROG	`(PARI) {a(n)=polcoeff(sum(m=0, n, (m+1)2^(m^2)x^m/(1-2^mx+xO(x^n))^m), n)}` `(PARI) {a(n)=if(n==0, 1, 2^n((n+1)2^n + 2)*(2^n + 1)^(n-2))}`
	CROSSREFS	`Cf. A171799, A171800.` `Sequence in context: A013113 A009105 A168481 * A091797 A265230 A007726` `Adjacent sequences: A171798 A171799 A171800 * A171802 A171803 A171804`
	KEYWORD	`nonn`
	AUTHOR	`Paul D. Hanna, Jan 20 2010`
	STATUS	`approved`

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 27 10:15 EST 2023. Contains 359838 sequences. (Running on oeis4.)