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 A007436 M1023 #30 Dec 26 2021 21:44:14 %S A007436 1,0,1,2,4,6,12,18,32,50,88,134,232,364,604,966,1596,2544,4180,6708, %T A007436 10932,17622,28656,46206,75020,121160,196384,317432,514228,831374, %U A007436 1346268,2177322,3524488,5701290,9227448,14927632,24157816,39083988 %N A007436 Moebius transform of Fibonacci numbers. %C A007436 After a(4) = 2, there are no primes in this sequence. Every element thereafter has at least two prime factors, the semiprimes (intersection of A007436 and A001358) starting 4, 6, 134, 831374, ... - _Jonathan Vos Post_, Dec 15 2004 %D A007436 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A007436 T. D. Noe, <a href="/A007436/b007436.txt">Table of n, a(n) for n = 1..500</a> %H A007436 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a> %F A007436 Row sums of the triangle generated by A054525 * A127647. - _Gary W. Adamson_, Jan 22 2007 %F A007436 G.f.: Sum_{n>=1} a(n)*x^n/(1 - x^n) = x/(1 - x - x^2). - _Ilya Gutkovskiy_, Apr 25 2017 %t A007436 mt[n_] := Block[{d = Divisors[n]}, Plus @@ (MoebiusMu /@ (n/d)*Fibonacci /@ d)]; Table[ mt[n], {n, 38}] (* _Robert G. Wilson v_ Dec 10 2004 *) %t A007436 a[n_] := DivisorSum[n, Fibonacci[#] MoebiusMu[n/#]&]; Array[a, 40] (* _Jean-François Alcover_, Dec 01 2015 *) %o A007436 (PARI) a(n)=sumdiv(n,d,fibonacci(d)*moebius(n/d)) %Y A007436 Cf. A001358. %K A007436 nonn,easy %O A007436 1,4 %A A007436 _N. J. A. Sloane_ %E A007436 More terms from _Robert G. Wilson v_, Dec 10 2004