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 A223830 #6 Jul 23 2025 04:34:50 %S A223830 239,57121,5995781,320423509,10278415020,222531132820,3529435151262, %T A223830 43488595659874,434747752662172,3644070166673656,26274461520805174, %U A223830 166299611386240948,939231697288055902,4797427977710396544 %N A223830 Number of nX7 0..2 arrays with rows and columns unimodal. %C A223830 Column 7 of A223831 %H A223830 R. H. Hardin, <a href="/A223830/b223830.txt">Table of n, a(n) for n = 1..56</a> %F A223830 Empirical: a(n) = (1296893401129/16938241367317436694528000000)*n^28 + (72703874510633/10888869450418352160768000000)*n^27 + (2880100345513/9489210850037779660800000)*n^26 + (861351630970627/93067260259985915904000000)*n^25 + (864800892388079/4136322678221596262400000)*n^24 + (2565528977681/696064173067468800000)*n^23 + (7905645181522433/151065697813310472192000)*n^22 + (12259447555207963/20064806380162252800000)*n^21 + (7483863495580993/1257623191919001600000)*n^20 + (3594050229364987331/73570956727261593600000)*n^19 + (49600789259036297/145619527485358080000)*n^18 + (86423411955717683177/42593711789467238400000)*n^17 + (1576780142566456509281/152001089131039948800000)*n^16 + (4463809610643909458677/97714985869954252800000)*n^15 + (251513003138559503557/1447629420295618560000)*n^14 + (130199265024314377939/227773859836723200000)*n^13 + (3852138142774912177207/2366317321637068800000)*n^12 + (298748214070779120271/74464531100467200000)*n^11 + (6476410200562687124239/757348083957104640000)*n^10 + (651582375522581245546751/41383663159084646400000)*n^9 + (81109174434756457340257/3242309791666176000000)*n^8 + (42338611909424523333083/1239706685048832000000)*n^7 + (8270024422491842435867/207147570023116800000)*n^6 + (132002526325134509056651/3366148012875648000000)*n^5 + (2188638685226111310011/68070993149263104000)*n^4 + (249241188258236233/11839806322344000)*n^3 + (742497212342827/64314997306560)*n^2 + (84445539769/20078358300)*n + 1 %e A223830 Some solutions for n=3 %e A223830 ..0..0..0..1..2..1..0....0..0..0..1..1..1..0....0..0..0..0..0..0..2 %e A223830 ..0..0..0..1..2..2..0....0..0..0..2..2..1..1....0..0..0..0..1..1..1 %e A223830 ..0..0..1..2..2..0..0....0..0..1..1..2..1..0....0..0..0..0..1..1..1 %K A223830 nonn %O A223830 1,1 %A A223830 _R. H. Hardin_ Mar 27 2013