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 A223797 #6 Jul 23 2025 04:31:58 %S A223797 130,16900,1658703,151310069,13602542576,1216562667529, %T A223797 108631485025292,9695922803812530,865293308203272685, %U A223797 77218182866179219113,6890814828420641198100,614921940899081513160269 %N A223797 Number of nX4 0..3 arrays with rows and antidiagonals unimodal. %C A223797 Column 4 of A223801 %H A223797 R. H. Hardin, <a href="/A223797/b223797.txt">Table of n, a(n) for n = 1..210</a> %F A223797 Empirical: a(n) = 130*a(n-1) -4151*a(n-2) +55367*a(n-3) -1103289*a(n-4) +25676564*a(n-5) -311713584*a(n-6) +2153547070*a(n-7) -14084700670*a(n-8) +111538734736*a(n-9) -678666743150*a(n-10) +3151156493032*a(n-11) -15705615808280*a(n-12) +74227237529348*a(n-13) -265525650225285*a(n-14) +858145104057893*a(n-15) -2835818034237058*a(n-16) +7784228337705693*a(n-17) -17375928755819704*a(n-18) +37062908059029592*a(n-19) -69764230981154356*a(n-20) +99762651233668576*a(n-21) -119132184363098064*a(n-22) +127177566453563712*a(n-23) -90807087696380928*a(n-24) +28396177139635200*a(n-25) -1473691515457536*a(n-26) +18962192793600*a(n-27) %e A223797 Some solutions for n=3 %e A223797 ..0..0..1..1....0..0..2..3....0..0..2..1....0..0..2..1....0..0..0..2 %e A223797 ..2..2..2..0....1..2..2..1....2..2..3..3....0..0..2..2....0..0..3..2 %e A223797 ..0..1..2..1....0..1..3..1....0..1..2..2....0..3..0..0....3..2..2..1 %K A223797 nonn %O A223797 1,1 %A A223797 _R. H. Hardin_ Mar 27 2013