The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A171801 O.g.f.: Sum_{n>=0} (n+1)*2^(n^2)*x^n/(1 - 2^n*x)^n. 2
 1, 4, 56, 2448, 379168, 223096896, 514098000000, 4691436926959872, 170097530401558168064, 24520599890836361905701888, 14055963692387060312500000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS 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 + 4*x + 56*x^2 + 2448*x^3 + 379168*x^4 +... A(x) = 1 + 2*2*x/(1-2*x) + 3*2^4*x^2/(1-2^2*x)^2 + 4*2^9*x^3/(1-2^3*x)^3 +... PROG (PARI) {a(n)=polcoeff(sum(m=0, n, (m+1)*2^(m^2)*x^m/(1-2^m*x+x*O(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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 12 12:20 EDT 2020. Contains 336439 sequences. (Running on oeis4.)