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 A223722 #6 Jul 23 2025 04:25:44 %S A223722 86,7396,273562,5537147,74140718,733129227,5733691150,37151436091, %T A223722 206162721823,1004293423046,4376877826065,17322507754495, %U A223722 63011209241684,212742488020655,672145108969951,2000883664124046,5644951281387772 %N A223722 Number of nX5 0..2 arrays with rows, antidiagonals and columns unimodal. %C A223722 Column 5 of A223725 %H A223722 R. H. Hardin, <a href="/A223722/b223722.txt">Table of n, a(n) for n = 1..187</a> %F A223722 Empirical: a(n) = (63370093/405483668029440000)*n^20 + (332923627/121645100408832000)*n^19 + (35260507/365849926041600)*n^18 + (11581079/8208171417600)*n^17 + (1549596019/89669099520000)*n^16 + (13415418209/62768369664000)*n^15 + (11281922929/8369115955200)*n^14 + (42712449023/3766102179840)*n^13 + (170811516793/3762339840000)*n^12 + (464597326061/877879296000)*n^11 - (328969296617/78829977600)*n^10 + (13832782422227/241416806400)*n^9 - (125724812428752281/313841848320000)*n^8 + (25263722436660997/11769069312000)*n^7 - (2160123866746163/269007298560)*n^6 + (37001904714133/1676505600)*n^5 - (815520542725887227/15878903040000)*n^4 + (13936490795992651/102918816000)*n^3 - (17701274883426919/53330659200)*n^2 + (9337885696189/21162960)*n - 143729 for n>5 %e A223722 Some solutions for n=3 %e A223722 ..0..0..0..0..0....0..2..2..2..2....0..1..1..2..1....0..2..2..2..1 %e A223722 ..0..1..1..1..1....0..2..2..1..0....0..1..2..2..1....0..1..1..2..1 %e A223722 ..0..2..0..0..0....1..2..1..1..0....0..1..2..2..2....1..1..1..2..1 %K A223722 nonn %O A223722 1,1 %A A223722 _R. H. Hardin_ Mar 26 2013