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 A070026 #11 Jun 13 2014 04:50:16 %S A070026 2,3,5,7,11,12,14,16,20,21,23,25,29,30,32,34,38,41,43,47,50,52,56,61, %T A070026 65,70,74,83,92,101,102,104,106,110,111,113,115,119,120,122,124,128, %U A070026 131,133,137,140,142,146,151,155,160,164,173,182,191,200,201,203,205,209,210,212,214,218 %N A070026 Initial, all intermediate and final iterated sums of digits of n are primes. %C A070026 2999 = A062802(4) is the smallest term of this sequence for which the second iterated sum of digits is not the final sum; i.e. the smallest requiring three summations (2+9+9+9=29, 2+9=11, 1+1=2 and all three sums are prime). (The corresponding statement about the very large A062802(5) is not true because a large number of smaller nonprimes of the same digit length also have the digit sum 2999, the least being 29999..., where 333 9's follow the 2.). A062802, a sequence of primes, is a subsequence of this sequence and of A070027. %C A070026 Additional terms can be generated by finding the next number whose digit sum is a prime already in the sequence. - _Felix Fröhlich_, Jun 13 2014 %H A070026 Alois P. Heinz, <a href="/A070026/b070026.txt">Table of n, a(n) for n = 1..1000</a> %e A070026 47 is here because 4+7=11 and 11 is prime while also 1+1=2 and 2 is prime. 39 (in A028835) is not a term: 3+9=12 is not prime - although 1+2=3 is prime. 49 (in A028834) is not a term: 4+9=13 is prime but 1+3=4 is not prime. %Y A070026 Cf. A028834 (Initial sum is prime), A028835 (Final sum is prime), A062802, A070027 (Primes from this sequence). %K A070026 base,easy,nonn %O A070026 1,1 %A A070026 _Rick L. Shepherd_, Apr 13 2002 %E A070026 Terms corrected by _Felix Fröhlich_, Jun 13 2014