The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A240333 Number of n X 2 0..3 arrays with no element equal to two plus the sum of elements to its left or two plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4. 1
 4, 15, 48, 125, 284, 582, 1097, 1932, 3219, 5123, 7846, 11631, 16766, 23588, 32487, 43910, 58365, 76425, 98732, 126001, 159024, 198674, 245909, 301776, 367415, 444063, 533058, 635843, 753970, 889104, 1043027, 1217642, 1414977, 1637189 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = (1/30)*n^5 + (1/24)*n^4 + (23/12)*n^3 - (193/24)*n^2 + (581/20)*n - 30 for n>2. Conjectures from Colin Barker, Oct 27 2018: (Start) G.f.: x*(4 - 9*x + 18*x^2 - 18*x^3 + 14*x^4 - 6*x^5 - x^6 + 2*x^7) / (1 - x)^6. a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>8. (End) EXAMPLE Some solutions for n=4: ..0..0....0..3....0..3....3..3....3..0....0..0....0..3....0..3....0..3....0..3 ..3..3....0..0....0..3....0..3....0..3....3..0....3..2....3..3....3..3....0..0 ..3..2....3..3....3..2....3..3....3..3....0..3....3..2....3..3....0..3....3..0 ..3..2....0..3....0..3....3..2....3..3....0..0....3..3....3..2....0..0....3..2 CROSSREFS Column 2 of A240338. Sequence in context: A307075 A219903 A238807 * A227099 A225976 A093967 Adjacent sequences:  A240330 A240331 A240332 * A240334 A240335 A240336 KEYWORD nonn AUTHOR R. H. Hardin, Apr 04 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 6 17:58 EST 2021. Contains 349567 sequences. (Running on oeis4.)