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 A113899 #10 Jul 11 2015 10:34:13 %S A113899 252,126,126,56,140,56,21,105,105,21,6,60,120,60,6,1,25,100,100,25,1, %T A113899 6,60,120,60,6,21,105,105,21,56,140,56,126,126,252 %N A113899 Number parallelogram based on Pascal's triangle (and special mirror of central and multiply of diagonal). %C A113899 .............................C(0,0)*C(10,5) %C A113899 ......................C(1,0)*C(9,5)...C(1,1)*C(9,4) %C A113899 ...............C(2,0)*C(8,5)...C(2,1)*C(8,4)...C(2,2)*C(8,3) %C A113899 ........C(3,0)*C(7,5)...C(3,1)*C(7,4)...C(3,2)*C(7,3)...C(3,3)*C(7,2) %C A113899 ...C(4,0)*C(6,5)...C(4,1)*C(6,4)...C(4,2)*C(6,3)...C(4,3)*C(8,2)...C(4,4)*C(6,1) %C A113899 C(5,0)*C(5,5)...C(5,1)*C(5,4)...C(5,2)*C(5,3)...C(5,3)*C(5,2)...C(5,4)*C(5,1)...C(5,5)*C(5,0) %C A113899 ...C(6,1)*C(4,4)...C(4,1)*C(6,4)...C(4,2)*C(6,3)...C(4,3)*C(8,2)...C(6,5)*C(4,0) %C A113899 ........C(7,2)*C(3,3)...C(7,3)*C(3,2)...C(7,4)*C(3,1)...C(7,5)*C(3,0) %C A113899 ...............C(8,3)*C(2,2)...C(8,4)*C(2,1)...C(8,5)*C(2,0) %C A113899 ......................C(9,4)*C(1,1)...C(9,5)*C(1,0) %C A113899 .............................C(10,5)*C(0,0) %C A113899 "m" matching: analog (permutations with exactly "m" fixed points. %C A113899 if aaaaabbbbb (a 5 letters b 5 letters) permutations compared aaaaaaaaaa (a 10 times letters) or compared bbbbbbbbbb (b 10 times letters then 252 "5" matching. ("5" matching: analog (permutations with exactly 5 fixed points.) %C A113899 If aaaaabbbbb (a 5 letters b 5 letters) permutations compared aaaaabbbbb (a 5 times letters b 5 times letters)then 1 "0" matching), 25 "2"matching 100 "4" matching, 100 "6" matching, 25 "8" matching and 1 "10" matching.(A008459 formatted as a triangular array: 6.rows) %C A113899 If aaaaabbbbb (a 5 letters b 5 letters) permutations compared abbbbbbbbb (a 1 times letters b 9 times letters) or aaaaaaaaab (a 9 times letters b 1 times letters) then 126 "4" and 126 "6" matching. %C A113899 etc... %C A113899 matching equivalent "fixed-point" %C A113899 example: %C A113899 arrangement relevant! %C A113899 compared %C A113899 letters %C A113899 times %C A113899 matching:0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....10 %C A113899 compared. %C A113899 letters.. %C A113899 times.... %C A113899 .a..b %C A113899 10..0.................................252.............................. %C A113899 .9..1...........................126.........126........................ %C A113899 .8..2......................56.........140..........56.................. %C A113899 .7..3................21.........105.........105..........21............ %C A113899 .6..4..........6...........60.........120..........60..........6....... %C A113899 .5..5....1...........25.........100.........100..........25...........1 %C A113899 .4..6..........6...........60.........120..........60..........6....... %C A113899 .3..7................21.........105.........105..........21............ %C A113899 .2..8......................56.........140..........56.................. %C A113899 .1..9...........................126.........126........................ %C A113899 0..10..................................252............................. %C A113899 matching.0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....10 %C A113899 The Maple code produces %C A113899 252, 126, 56, 21, 6, 1 %C A113899 126, 140, 105, 60, 25, 6 %C A113899 56, 105, 120, 100, 60, 21 %C A113899 21, 60, 100, 120, 105, 56 %C A113899 6, 25, 60, 105, 140, 126 %C A113899 1, 6, 21, 56, 126, 252 %C A113899 which is the table rotated right by Pi/4. %p A113899 for n from 0 to 5 do seq(binomial(i,n)*binomial(10-i,5-n), i=0+n..10-5+n ); # _Zerinvary Lajos_, Mar 31 2009 %Y A113899 Cf. A113162, A113163, A113164. %K A113899 easy,fini,nonn,uned %O A113899 0,1 %A A113899 _Zerinvary Lajos_, Jan 29 2006, May 28 2007