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

 Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS"). Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A249892 G.f.: Sum_{n>=0} x^n / (1 - n*x - n^2*x^2). 0
 1, 1, 2, 5, 15, 52, 207, 923, 4532, 24271, 140581, 874434, 5806557, 40955973, 305544958, 2402139329, 19837601155, 171598571288, 1550865447043, 14611295961047, 143210242799872, 1457573997373131, 15379106145570681, 167962044452359398, 1896100883094424657, 22096376018936592193 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS From Vaclav Kotesovec, Nov 09 2014: (Start) (a(n))^(1/n) ~ phi^(1-1/w) * n^(1-1/w) / w^(1-1/w), where w = LambertW(phi*e*n). Limit n->infinity a(n)^(1/n) * LambertW(phi*e*n) / n = phi/e, where phi = (1+sqrt(5))/2 = A001622. (End) LINKS FORMULA a(n) = Sum_{k=0..n} Fibonacci(n-k+1) * k^(n-k). EXAMPLE G.f.: A(x) = 1 + x + 2*x^2 + 5*x^3 + 15*x^4 + 52*x^5 + 207*x^6 +... where A(x) = 1 + x/(1-x-x^2) + x^2/(1-2*x-4*x^2) + x^3/(1-3*x-9*x^2) + x^4/(1-4*x-16*x^2) +  x^5/(1-5*x-25*x^2) + x^6/(1-6*x-36*x^2) + x^7/(1-7*x-49*x^2) +... MATHEMATICA Flatten[{1, Table[Sum[Fibonacci[n-k+1] * k^(n-k), {k, 0, n}], {n, 1, 20}]}] (* Vaclav Kotesovec, Nov 09 2014 *) PROG (PARI) {a(n)=polcoeff((sum(m=0, n, x^m/(1-m*x-m^2*x^2 +x*O(x^n)))), n)} for(n=0, 30, print1(a(n), ", ")) (PARI) {a(n)=sum(k=0, n, fibonacci(n-k+1)*k^(n-k))} for(n=0, 30, print1(a(n), ", ")) CROSSREFS Cf. A000045. Sequence in context: A186001 A134381 A107589 * A006790 A007548 A328431 Adjacent sequences:  A249889 A249890 A249891 * A249893 A249894 A249895 KEYWORD nonn AUTHOR Paul D. Hanna, Nov 08 2014 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 November 30 02:42 EST 2020. Contains 338781 sequences. (Running on oeis4.)