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 A160966 #6 Mar 31 2012 10:31:25 %S A160966 2,6,11,25,45,94,176,361,700,1405,2752,5533,10964,22011,43839,87868, %T A160966 175557,351746,703243,1407705,2814709,5631461,11261009,22524901, %U A160966 45044446,90091251,180165450,360333977,720640449,1441293048,2882532607 %N A160966 Starting from a(1)=2, a(n) = A028260(1+a(n-1)) if n is even, a(n) = A026424(a(n-1)) if n is odd. %C A160966 If a(1) were set to 3, the equivalent sequence would start 3, 9, 17, 38, 71, 146, 279,... %C A160966 Alternatively starting from a(1)=4 we get 4, 10, 18, 39, 72, 150,.. %e A160966 a(2)= 6, the second integer containing an even number of prime factors. %e A160966 a(3)= 11, the sixth integer containing an odd number of primes. %Y A160966 Cf. A141436 %K A160966 nonn %O A160966 1,1 %A A160966 _Daniel Tisdale_, May 31 2009 %E A160966 Definition clarified, sequence extended beyond 25 by _R. J. Mathar_, May 31 2010 %E A160966 a(15)-a(31) from _Donovan Johnson_, Jul 02 2010