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 A264453 #4 Nov 14 2015 07:41:29 %S A264453 2,41,492,4851,44291,394154,3502159,31450283,287335089,2680535274, %T A264453 25586566853,250169461829,2506738712869,25745302689807, %U A264453 270994937686871,2922760610595872,32288420619988347,365214362676429903,4227719744153328064,50063651356822568135 %N A264453 Number of permutations of [n] with exactly four (possibly overlapping) occurrences of the generalized pattern 12-3. %H A264453 Alois P. Heinz, <a href="/A264453/b264453.txt">Table of n, a(n) for n = 5..500</a> %Y A264453 Column k=4 of A260665. %K A264453 nonn %O A264453 5,1 %A A264453 _Alois P. Heinz_, Nov 14 2015