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 A175508 #15 Oct 23 2023 17:40:44 %S A175508 1,1,1,3,2,4,3,7,5,7,6,10,7,10,9,15,10,14,11,17,13,17,14,22,16,20,19, %T A175508 24,19,24,20,31,23,27,23,32,25,30,27,37,28,34,29,39,33,37,32,46,33,41, %U A175508 37,46,37,46,40,52,41,48,42,54,43,51,47,63,47,56,48,61,51,58,51,68,52,62 %N A175508 a(n) is the difference of n and the product of the indices of prime factors of n with multiplicity, a(1) = 0. %C A175508 Original name: If p is the product of k1-th prime, k2-th prime,..,kr-th prime then set a(n)=n-k1*k2*..*kr, if p is the k-th prime then set=n-k, a(1)=1 by convention. - _Michael De Vlieger_, Oct 23 2023 %H A175508 Michael De Vlieger, <a href="/A175508/b175508.txt">Table of n, a(n) for n = 1..10000</a> %F A175508 a(n) = n - A003963(n) for n>1. %t A175508 Array[# - Times @@ PrimePi@ Flatten[ConstantArray[#1, #2] & @@@ FactorInteger[#]] &, 74] (* _Michael De Vlieger_, Oct 23 2023 *) %Y A175508 Cf. A003963. %K A175508 nonn %O A175508 1,4 %A A175508 _Juri-Stepan Gerasimov_, Jun 03 2010 %E A175508 a(34) corrected by _Georg Fischer_, Dec 11 2022 %E A175508 Name edited by _Michael De Vlieger_, Oct 23 2023