# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a102311 Showing 1-1 of 1 %I A102311 #14 Mar 18 2023 23:04:30 %S A102311 0,1,2,7,22,86,414,2521,19494,191695,2397716,38148444,772057396, %T A102311 19875413009,650843469738,27110077916903,1436411242814058, %U A102311 96810095832996034,8299583912379548210,905077596297808256825,125547805293905152853710,22152679283963321048140511 %N A102311 a(n) = Sum_{k=1..n} Fibonacci(k*(n-k)). %F A102311 G.f.: Sum_{n>=1} Fibonacci(n)*x^(n+1) / (1 - Lucas(n)*x + (-1)^n*x^2), where Lucas(n) = A000204(n). - _Paul D. Hanna_, Jan 28 2012 %F A102311 a(n) ~ c * phi^(n^2/4), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio and c = 1.14267253730874516106624178718900147373346430046702447860265114357421... - _Vaclav Kotesovec_, Jan 08 2021 %t A102311 Table[Sum[Fibonacci[k(n-k)],{k,n}],{n,30}] (* _Harvey P. Dale_, Jul 03 2019 *) %o A102311 (PARI) {a(n)=sum(k=1,n,fibonacci(k*(n-k)))} %o A102311 (PARI) {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)} %o A102311 {a(n)=polcoeff(sum(m=1,n,fibonacci(m)*x^(m+1)/(1-Lucas(m)*x+(-1)^m*x^2+x*O(x^n))),n)} /* Paul D. Hanna, Jan 28 2012 */ %Y A102311 Cf. Antidiagonal sums of array A102310. %Y A102311 Cf. A000204, A001622. %K A102311 nonn %O A102311 1,3 %A A102311 _Ralf Stephan_, Jan 06 2005 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE