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 A242589 #22 Oct 21 2014 03:20:48 %S A242589 5,19,37,43,97,107,6091,6389,7121,21727,147107,148151,148279,148429, %T A242589 148469,172877,173209,173741,2621387,5642293,5642321,8932771,8981827, %U A242589 8981879,9094979,9095089,9997783,10010687,10010789,10037749,10144523,40179929,40365217,40379077,40379197,40386811,40612933 %N A242589 Primes p such that p = the cumulative sum of the digit-sum in base 15 of the digit-product in base 4 of each prime < p. %F A242589 sum = sum + digit-sum(digit-mult(prime,base=4),base=15). The function digit-mult(n) multiplies all digits d of n, where d > 0. For example, digit-mult(1230) = 1 * 2 * 3 = 6. Therefore, the digit-sum in base 15 of the digit-mult(333) in base 4 = digit-sum(3 * 3 * 3) = digit-sum(1C) = 1 + C = 13. (1C in base 15 = 27 in base 10). %e A242589 5 = digit-sum(digit-mult(2,b=4),b=15) + sum(mult(3,b=4),b=15) = 2 + 3. %e A242589 19 = digit-sum(digit-mult(2,b=4),b=15) + sum(mult(3,b=4),b=15) + sum(mult(11,b=4),b=15) + sum(mult(13,b=4),b=15) + sum(mult(23,b=4),b=15) + sum(mult(31,b=4),b=15) + sum(mult(101,b=4),b=15) = 2 + 3 + 1 + 3 + 6 + 3 + 1. %Y A242589 Cf. A240886 (similar sequence with digit sums in base 3). %K A242589 nonn,base %O A242589 1,1 %A A242589 _Anthony Sand_, May 20 2014