This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A174331 #14 Sep 08 2019 10:05:41 %S A174331 1,2,6,8,9,10,14,18,19,20,22,26,27,28,30,31,32,34,40,41,42,52,53,55, %T A174331 59,61,64,66,71,73,74,77,79,85,87,89,92,93,94,95,97,99,101,107,109, %U A174331 113,115,116,117,120,121,123,125,127,128,129,130,133,135,138,143,146,147,149 %N A174331 n such that tau(Fibonacci(n)) is a perfect square. %C A174331 tau = A000005 is the number of divisors of n. %H A174331 Amiram Eldar, <a href="/A174331/b174331.txt">Table of n, a(n) for n = 1..423</a> %F A174331 {n: A063375(n) in A000290}. - _R. J. Mathar_, Jul 09 2012 %e A174331 40 is in the sequence because tau(Fibonacci(40)) = tau(102334155) = 64 is square. %t A174331 Select[Range[150], IntegerQ[Sqrt[DivisorSigma[0,Fibonacci[#]]]] &] %o A174331 (PARI) is(n) = issquare(numdiv(fibonacci(n))) \\ _Felix Fröhlich_, Sep 08 2019 %Y A174331 Cf. A000005, A000045, A000290, A036436, A063375. %K A174331 nonn %O A174331 1,2 %A A174331 _Michel Lagneau_, Mar 15 2010