This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A211891 G.f.: exp( Sum_{n>=1} 2 * Pell(n^2) * x^n/n ), where Pell(n) = A000129(n). 1
 1, 2, 14, 682, 236826, 525175434, 7101054148862, 575978478770467714, 277997363115795461721154, 794462328877965002894838885122, 13398419999037765629218732004567606814, 1330302023374557034879527995005574743144202826 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Given g.f. A(x), note that A(x)^(1/2) is not an integer series. LINKS EXAMPLE G.f.: A(x) = 1 + 2*x + 14*x^2 + 682*x^3 + 236826*x^4 + 525175434*x^5 +... such that log(A(x))/2 = x + 12*x^2/2 + 985*x^3/3 + 470832*x^4/4 + 1311738121*x^5/5 + 21300003689580*x^6/6 + 2015874949414289041*x^7/7 +...+ Pell(n^2)*x^n/n +... Pell numbers begin: A000129 = [1,2,5,12,29,70,169,408,985,2378,5741,13860,33461,...]. PROG (PARI) {Pell(n)=polcoeff(x/(1-2*x-x^2+x*O(x^n)), n)} {a(n)=polcoeff(exp(sum(k=1, n, 2*Pell(k^2)*x^k/k)+x*O(x^n)), n)} for(n=0, 20, print1(a(n), ", ")) CROSSREFS Cf. A208056, A211892, A000129 (Pell), A204327 (Pell(n^2)). Sequence in context: A156172 A013036 A075044 * A060599 A319774 A065868 Adjacent sequences:  A211888 A211889 A211890 * A211892 A211893 A211894 KEYWORD nonn AUTHOR Paul D. Hanna, Apr 24 2012 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 May 25 22:17 EDT 2019. Contains 323576 sequences. (Running on oeis4.)