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 A235680 #20 Aug 11 2015 01:29:11 %S A235680 2,191,163,151,127,1644997,36778597,935715673,50682890749, %T A235680 16390560362269,63334172492839 %N A235680 The smallest first term of a sequence of n primes such that, after the first, each is equal to the previous prime plus the sum of all of its digits, plus the product of all of its nonzero digits. %C A235680 The following term produced in each sequence after the n-th is necessarily a composite integer. %H A235680 C. Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_727.htm">Puzzle 727. Extending the OEIS sequence A235680</a> %e A235680 Example for n=8: a(8)=935715673 because after it the seven primes are 936311069, 936337351, 936490481, 936677149, 938391809, 938811763 and 939029537, with 936311069 = 935715673 + 9*3*5*7*1*5*6*7*3+(9+3+5+7+1+5+6+7+3) and so on... %Y A235680 Cf. A233692, A233783, A090009. %K A235680 nonn,hard,more,base %O A235680 1,1 %A A235680 _Carlos Rivera_, Jan 13 2014 %E A235680 a(9) from _Giovanni Resta_, Jan 13 2014 %E A235680 a(10)-a(11) from _Giovanni Resta_, Feb 22 2014