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 A101754 #6 Nov 21 2013 12:48:36 %S A101754 9,11,14,22,23,25,31,32,39,45,46,55,56,57,63,64,68,73,78,81,84,90,94, %T A101754 112,115,117,162,163,169,172,179,184,200,208,212,221,227,233,240,253, %U A101754 270,272,283,290,303,327,329,339,345,347,348,365,378,381,396,398,409 %N A101754 Numbers n such that the sum of the first n decimal places of Catalan's constant is prime. %e A101754 The sums of the first n decimal places of Catalan's constant are listed in A099616: 9, 10, 15, 24, 30, 35, 40, 49, 53, 54, 61, ... Of these, the first one that is prime is 53 which is the 9th term. The first term in our sequence is therefore 9. The partial sum 61 is also prime and this appears in the 11th place, so the second term of our sequence is 11. %t A101754 Flatten[Position[Accumulate[RealDigits[N[Catalan,500]][[1]]], _?PrimeQ]] (* _Harvey P. Dale_, May 10 2011 *) %Y A101754 Cf. A099616. %K A101754 nonn,base %O A101754 1,1 %A A101754 Mark Hudson (mrmarkhudson(AT)hotmail.com), Dec 15 2004