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 A174027 #12 Apr 15 2014 02:50:50 %S A174027 35,25,49,65,77,143,55,91,121,169,95,119,209,221,323,65,133,187,247, %T A174027 289,361,125,161,275,299,425,437,575,115,175,253,325,391,475,529,625, %U A174027 155,203,341,377,527,589,713,725,899,145,217,319,403,493,569,667,775,841 %N A174027 Alternating triangle (version 2) read by rows: composites k such that k=6*m-+1=r*j r>=j and n>=q>0 where r=6*n-1 or r=6*n+1 and j=6*q-1 or j=6*q+1. %C A174027 Composites of form 6*m-1 are in even (0,2,4,..) rows of alternating triangle only. Composites of form 6*m+1 are in odd (1,3,5,..) rows of alternating triangle only. 1 UNION nontrivial primes UNION A174027(without repetition) = A140475 U A174027(without repetition) = A007310 = numbers of form 6*n+-1, where alternating triangle (version 1) is A173865. %e A174027 Triangle begins: %e A174027 35(=7*5) in even 0th row; %e A174027 25(=5*5) and 49(=7*7) in odd 1st row; %e A174027 65(=13*5), 77(=11*7) and 143(=13*11) in even 2nd row. %Y A174027 Cf. A007310, A140475, A173825, A173865. %K A174027 nonn,tabl,uned %O A174027 1,1 %A A174027 _Juri-Stepan Gerasimov_, Mar 06 2010, Mar 17 2010