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 A108667 #5 Feb 27 2015 18:54:07 %S A108667 20,34,57,48,80,112,62,103,144,185,76,126,176,226,276,90,149,208,267, %T A108667 326,385,104,172,240,308,376,444,512,118,195,272,349,426,503,580,657, %U A108667 132,218,304,390,476,562,648,734,820,146,241,336,431,526,621,716,811 %N A108667 Triangle read by rows: T(n,k) = 9k*n + 14(n+k) + 20 (0 <= k <= n). %C A108667 Kekulé numbers for certain benzenoids. T(n,n) = 9n^2 + 28n + 20 = A051872(n+2). %D A108667 S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 102). %F A108667 G.f.: (20 - 6z - 3t*z + t^2*z^2 - 16t*z^2 - 4t^2*z^3)/((1-z)^2*(1-t*z)^3). %e A108667 Triangle begins: %e A108667 20; %e A108667 34,57; %e A108667 48,80,112; %e A108667 62,103,144,185; %p A108667 T:=proc(n,k) if k<=n then 9*k*n+14*(n+k)+20 else 0 fi end: for n from 0 to 10 do seq(T(n,k),k=0..n) od; # yields sequence in triangular form %Y A108667 Cf. A051872. %K A108667 nonn,tabl %O A108667 0,1 %A A108667 _Emeric Deutsch_, Jun 14 2005