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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.

A223868 Number of 5Xn 0..3 arrays with rows and antidiagonals unimodal and columns nondecreasing.

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%I A223868 #6 Jul 23 2025 04:36:41
%S A223868 56,3136,93731,1771012,23738426,243933798,2030417942,14256118510,
%T A223868 87061570336,473468963674,2335341201122,10598137054237,44753111308505,
%U A223868 177414858857953,664941648534183,2369386354876666,8063121237072325
%N A223868 Number of 5Xn 0..3 arrays with rows and antidiagonals unimodal and columns nondecreasing.
%C A223868 Row 5 of A223864
%H A223868 R. H. Hardin, <a href="/A223868/b223868.txt">Table of n, a(n) for n = 1..210</a>
%F A223868 Empirical: a(n) = (1/7353420799762759680000000)*n^30 + (1/70032579045359616000000)*n^29 + (44267/43995432122902432972800000)*n^28 + (7069/142935127104946176000000)*n^27 + (7664593067/4032914611266056355840000000)*n^26 + (95633173/1590893337777537024000000)*n^25 + (12116718221/7445380820798873272320000)*n^24 + (43392644761/1128088003151344435200000)*n^23 + (167454195287/207507826666635264000000)*n^22 + (15612731/1026631177076736000)*n^21 + (231683957839/891769172451655680000)*n^20 + (66096734083147/16349101494947020800000)*n^19 + (200461940945639/3520141470203904000000)*n^18 + (1823522533638571/2581437078149529600000)*n^17 + (1303802945440133/173715530435474227200)*n^16 + (484634612399204963/7238147101478092800000)*n^15 + (230088704266434095413/461431877719228416000000)*n^14 + (667759304130635953/215119756512460800000)*n^13 + (1965055074194837421509/121392078599981629440000)*n^12 + (652130907487529444879/9196369590907699200000)*n^11 + (209880428234740913519/803878460743680000000)*n^10 + (4164931672385398837/5171147993088000000)*n^9 + (18238486469597047158809/8813187524619878400000)*n^8 + (16125843259442502284221/3672161468591616000000)*n^7 + (512520751978071205586267/67322960257512960000000)*n^6 + (11886431938356946376363/1122049337625216000000)*n^5 + (280599068064199101557/24311068981879680000)*n^4 + (63983220995615011/6697264182336000)*n^3 + (1678025791833176033/279770238283536000)*n^2 + (230910956201/110909026800)*n + 1
%e A223868 Some solutions for n=3
%e A223868 ..0..0..0....0..1..1....2..0..0....0..0..0....1..1..0....1..0..0....0..0..0
%e A223868 ..0..0..0....0..1..1....2..2..0....0..0..1....2..1..1....1..1..1....0..1..0
%e A223868 ..1..0..0....0..1..2....2..3..1....1..1..3....2..2..1....1..1..2....2..2..0
%e A223868 ..2..3..0....0..3..2....3..3..3....1..3..3....2..2..2....3..3..3....2..2..3
%e A223868 ..2..3..1....3..3..3....3..3..3....1..3..3....3..3..3....3..3..3....2..3..3
%K A223868 nonn
%O A223868 1,1
%A A223868 _R. H. Hardin_ Mar 28 2013