%I #43 Apr 13 2024 12:42:58

%S 1,1,3,4,6,15,14,32,54,72,90,403,234,420,1116,1536,1598,5400,4332,

%T 12096,17724,18000,28658,157248,93062,122148,320760,473760,514230,

%U 2142720,1349244,3391488,5346540,5708056,11924808,48211200,24664200

%N a(n) is the sum of the divisors of Fibonacci(n) (A000045).

%H Amiram Eldar, <a href="/A063477/b063477.txt">Table of n, a(n) for n = 1..1408</a> (terms 1..1000 from T. D. Noe using Blair Kelly's data)

%H Blair Kelly, <a href="http://mersennus.net/fibonacci/">Fibonacci and Lucas Factorizations</a>.

%H Florian Luca, <a href="https://www.fq.math.ca/Scanned/37-3/luca.pdf">Arithmetic Functions of Fibonacci Numbers</a>, The Fibonacci Quarterly, Vol. 37, No. 3 (1999), pp. 265-268.

%F a(n) = sigma(A000045(n)) = A000203(A000045(n)). - _Omar E. Pol_, Dec 20 2008

%F a(n) <= A000045(A000203(n)), with equality if and only if n = 1 or 3 (Luca, 1999). - _Amiram Eldar_, Jan 12 2022

%t DivisorSigma[1, Fibonacci@Range@40] (* _Vladimir Reshetnikov_, Nov 13 2015 *)

%o (PARI) j=[]; for(n=1,50,j=concat(j, sigma(fibonacci(n)))); j

%o (Sage) [sigma(fibonacci(n),1) for n in range(1,38)] # _Zerinvary Lajos_, Jun 04 2009

%Y Cf. A000045, A000203.

%K nonn

%O 1,3

%A _Jason Earls_, Jul 28 2001