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 A058893 #6 Jun 29 2017 03:37:16 %S A058893 1,5,9,22,112,118,93,899,2346,1773,386,5940,27446,48426,28650,1586, %T A058893 35138,247752,745180,995290,484578 %N A058893 Triangle arising in enumeration of maps on projective plane. %H A058893 E. A. Bender, E. R. Canfield and R. W. Robinson, <a href="http://dx.doi.org/10.4153/CMB-1988-039-4">The enumeration of maps on the torus and the projective plane</a>, Canad. Math. Bull., 31 (1988), 257-271; see p. 270. %e A058893 Triangle starts: %e A058893 1; %e A058893 5,9; %e A058893 22,112,118; %e A058893 93,899,2346,1773; %e A058893 ... %Y A058893 A000346 is first column. %K A058893 nonn,tabl,more %O A058893 1,2 %A A058893 _N. J. A. Sloane_, Jan 08 2001