A234993 Number of (n+1) X (2+1) 0..6 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).

916, 5112, 32256, 229228, 1687256, 12776172, 97629440, 752520988, 5824747252, 45284344160, 353135357040, 2762273406552, 21660322695280, 170249261469892, 1340831389878956, 10579388163812412, 83606019194998580, 661659841902050452

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 6*a(n-1) +145*a(n-2) -752*a(n-3) -9334*a(n-4) +41421*a(n-5) +350517*a(n-6) -1354277*a(n-7) -8617439*a(n-8) +29691561*a(n-9) +147908106*a(n-10) -465456923*a(n-11) -1844354978*a(n-12) +5418592827*a(n-13) +17142962010*a(n-14) -47956757782*a(n-15) -120746606447*a(n-16) +327447020322*a(n-17) +650926343809*a(n-18) -1740121457481*a(n-19) -2698809487907*a(n-20) +7230222191327*a(n-21) +8610347154836*a(n-22) -23519481347436*a(n-23) -21060770608040*a(n-24) +59812533502435*a(n-25) +39165695095186*a(n-26) -118451096631369*a(n-27) -54588838411578*a(n-28) +181491721699373*a(n-29) +55729099282996*a(n-30) -213160956817772*a(n-31) -40145457720166*a(n-32) +189498178497244*a(n-33) +19155239362192*a(n-34) -125401972381171*a(n-35) -5433880826151*a(n-36) +60455696914684*a(n-37) +890128451025*a(n-38) -20656751347661*a(n-39) -330921215331*a(n-40) +4825908656200*a(n-41) +227383374666*a(n-42) -729157775008*a(n-43) -75605102388*a(n-44) +62860038344*a(n-45) +11433294720*a(n-46) -2022154176*a(n-47) -653147712*a(n-48) -43972992*a(n-49).

Example

Some solutions for n=3:
  3 2 3   3 6 3   0 1 2   5 6 5   4 1 4   3 4 1   2 5 0
  6 3 6   2 3 2   6 5 4   2 5 2   6 5 6   2 5 4   3 4 1
  5 0 5   6 5 6   3 4 1   0 1 0   5 6 5   1 2 3   6 5 4
  6 3 6   5 6 5   2 5 4   5 4 5   3 2 3   4 3 2   3 4 1

Crossrefs

Column 2 of A234998.

Sequence in context: A365514 A252427 A074887 * A234764 A282592 A029897

Adjacent sequences: A234990 A234991 A234992 * A234994 A234995 A234996

Keyword

nonn

Author

R. H. Hardin, Jan 02 2014

Status

approved