cp's OEIS Frontend

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.

A224175 Number of 4 X n 0..3 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.

Original entry on oeis.org

35, 1225, 22988, 272130, 2335459, 15925611, 91494280, 459681672, 2071283343, 8522430293, 32452346859, 115542470121, 387735671674, 1234254138386, 3746228897820, 10888055937498, 30409729685443, 81862695894551, 212957974479177, 536558013233411, 1311963232523951
Offset: 1

Views

Author

R. H. Hardin, Mar 31 2013

Keywords

Examples

			Some solutions for n=3:
..0..0..1....0..3..1....1..2..0....0..1..1....0..1..1....0..1..1....0..1..0
..0..2..3....3..3..1....1..3..3....0..2..2....0..1..3....1..2..1....3..1..1
..1..2..3....3..3..1....3..3..3....0..2..2....0..3..3....1..2..2....3..2..1
..2..2..3....3..3..3....3..3..3....3..2..2....2..3..3....3..3..3....3..2..2
		

Crossrefs

Row 4 of A224173.

Formula

Empirical: a(n) = (1/2906843957821440000)*n^24 + (1/80745665495040000)*n^23 + (40627/53523844179886080000)*n^22 + (149/6436248698880000)*n^21 + (6593077/9731608032706560000)*n^20 + (3395111/221172909834240000)*n^19 + (6648319/21341245685760000)*n^18 + (58653979/10670622842880000)*n^17 + (28432949/331085905920000)*n^16 + (2936797909/2510734786560000)*n^15 + (18556527629/1369491701760000)*n^14 + (39701629159/289700167680000)*n^13 + (122790999059713/110472330608640000)*n^12 + (19552381958779/2510734786560000)*n^11 + (343066282192637/7532204359680000)*n^10 + (2966503457023/14265538560000)*n^9 + (24242241250827793/32011868528640000)*n^8 + (16514299013828449/8002967132160000)*n^7 + (364205524025441321/152056375511040000)*n^6 + (32838681788587261/2111894104320000)*n^5 - (148032441802153/14768490240000)*n^4 - (1586985136748719/5866372512000)*n^3 + (228836377537124017/148419224553600)*n^2 - (1300791949339/411863760)*n + 2639 for n>2.

Extensions

Name corrected by Andrew Howroyd, Mar 18 2025