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 A131801 #4 Mar 31 2012 13:23:38 %S A131801 1,3,9,15,27,45,105,81,135,225,315,1155,243,405,675,945,1575,3465, %T A131801 15015,729,1215,2025,3375,2835,4725,10395,11025,17325,45045,255255, %U A131801 2187,3645,6075,10125,8505,14175,23625,31185,33075,51975,121275,135135,225225 %N A131801 Increment each prime factor for each term of the least prime sequence A087443. %F A131801 T(n,k) = A003961[A087443(n,k)]. - _R. J. Mathar_, Aug 01 2007 %e A131801 The term 30 = 2*3*5 %e A131801 becomes 105 = 3*5*7 %e A131801 A087443 begins %e A131801 1 %e A131801 2 %e A131801 4...6 %e A131801 8...12...30 %e A131801 16 %e A131801 etc %e A131801 so a(n) begins %e A131801 1 %e A131801 3 %e A131801 9...15 %e A131801 27..45..105 %e A131801 81 %e A131801 etc %Y A131801 Cf. A025487. %Y A131801 Cf. A131822. %K A131801 easy,tabf,nonn %O A131801 0,2 %A A131801 _Alford Arnold_, Jul 16 2007 %E A131801 More terms from _R. J. Mathar_, Aug 01 2007