A121569 - OEIS

%I #4 Jun 12 2017 16:01:19

%S 1,2,4,12,20,54,88,232,986,1596,6764,17710,28656,75024,317810,1346268,

%T 2178308,9227464,24157816,39088168,165580140,433494436,1836311902,

%U 12586269024,32951280098,53316291172,139583862444,225851433716

%N a(n) = Fibonacci((prime(n)+3)/2) - 1.

%C p = Prime[n] divides a(n) for p = {29,89,101,181,229,349,401,461,509,521,541,709,761,769,809,...} = A047650[n] Primes for which golden mean tau is a quadratic residue or Primes of the form x^2+20y^2.

%F a(n) = Fibonacci[ (Prime[n]+3)/2 ] - 1, n>1. a(n) = Sum[ Fibonacci[k], {k,1,(p-1)/2} ], p = Prime[n], n>1.

%t Table[Fibonacci[(Prime[n]+3)/2]-1,{n,2,50}]

%Y Cf. A000045, A121567, A121568, A033205, A045468, A064739, A047650.

%K nonn

%O 2,2

%A _Alexander Adamchuk_, Aug 08 2006