login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

A269204
Number of 4Xn 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three no more than once.
1
256, 15540, 471492, 15289548, 463790340, 13753913556, 399104835612, 11402099212308, 321701652077076, 8985658235129964, 248904744378939924, 6846738391062856596, 187219797100389992412, 5093241917191742737620
OFFSET
1,1
COMMENTS
Row 4 of A269201.
LINKS
FORMULA
Empirical: a(n) = 48*a(n-1) -424*a(n-2) -5664*a(n-3) +40624*a(n-4) +218356*a(n-5) -1300662*a(n-6) -2980700*a(n-7) +17916384*a(n-8) +2629424*a(n-9) -96328452*a(n-10) +132185980*a(n-11) -10936481*a(n-12) -91456900*a(n-13) +51588388*a(n-14) +9975760*a(n-15) -14279120*a(n-16) +2348160*a(n-17) +465152*a(n-18) -79872*a(n-19) -9216*a(n-20)
EXAMPLE
Some solutions for n=2
..3..1. .0..2. .1..1. .3..3. .3..1. .2..3. .3..2. .2..2. .0..3. .3..2
..3..2. .0..1. .1..3. .2..3. .1..1. .1..0. .3..1. .3..2. .2..0. .2..3
..3..3. .0..0. .3..1. .3..3. .1..1. .0..2. .1..3. .2..0. .1..3. .2..3
..1..2. .1..1. .3..3. .0..1. .2..3. .2..0. .1..1. .1..3. .2..0. .2..2
CROSSREFS
Cf. A269201.
Sequence in context: A238073 A017032 A136286 * A224283 A224206 A238064
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 20 2016
STATUS
approved