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 A286225 #11 Feb 16 2025 08:33:44
%S A286225 1,1,1,1,1,1,2,3,4,5,7,9,13,18,25,34,46,61,83,112,153,209,286,387,526,
%T A286225 713,969,1317,1794,2437,3312,4497,6110,8302,11290,15347,20865,28354,
%U A286225 38533,52361,71167,96721,131464,178672,242834,330020,448532,609590,828511,1126037,1530418,2079977,2826896,3841998
%N A286225 Number of compositions (ordered partitions) of n into parts with an even number of distinct prime divisors.
%H A286225 Amiram Eldar, <a href="/A286225/b286225.txt">Table of n, a(n) for n = 0..7000</a>
%H A286225 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DistinctPrimeFactors.html">Distinct Prime Factors</a>
%H A286225 <a href="/index/Com#comp">Index entries for sequences related to compositions</a>
%F A286225 G.f.: 1/(1 - Sum_{k>=1} x^A030231(k)).
%e A286225 a(8) = 4 because we have [6, 1, 1], [1, 6, 1], [1, 1, 6] and [1, 1, 1, 1, 1, 1, 1, 1].
%t A286225 nmax = 53; CoefficientList[Series[1/(1 - Sum[Boole[EvenQ[PrimeNu[k]]] x^k, {k, 1, nmax}]), {x, 0, nmax}], x]
%Y A286225 Cf. A030231, A285798, A286221, A286224.
%K A286225 nonn
%O A286225 0,7
%A A286225 _Ilya Gutkovskiy_, May 04 2017