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 A155898 #6 Apr 20 2013 04:52:43 %S A155898 1,1,1,1,0,1,0,0,1,1,0,0,0,0,0,0,0,1,0,1,1,0,0,0,0,1,1,1,0,1,1,0,0,0, %T A155898 0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1,1,0,0,0,0,1,0,0,0,1,0,0,0, %U A155898 0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,1,0,0,0,1 %N A155898 Square matrix T(m,n)=1 if (2m+1)^(2n)-2 is prime, 0 otherwise; read by antidiagonals. %C A155898 In some sense the "minimal" possible generalization of the pattern of Mersenne primes (cf. A000043) is to consider powers of odd numbers minus 2. Here only even powers are considered (which obviously correspond to an odd power of the base squared). %o A155898 (PARI) T = matrix( 19,19,m,n, isprime((2*m+1)^(2*n)-2)) ; %o A155898 A155898 = concat( vector( vecmin( matsize(T)), i, vector( i, j, T[j,i-j+1]))) %Y A155898 Cf. A084714, A128472, A014224, A109080, A090669, A128455, A128457, A128458, A128459, A128460, A128461. %K A155898 easy,nonn,tabl %O A155898 1,1 %A A155898 _M. F. Hasler_, Feb 01 2009