A234724 Number of (n+1) X (4+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7 (constant-stress 1 X 1 tilings).

19120, 48976, 116168, 357208, 1000264, 3403528, 10632200, 38594056, 129877960, 493469896, 1750807688, 6882950728, 25404230344, 102540693448, 390317557640, 1608662074696, 6277331314120, 26307807293896, 104776708099208

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..135

Formula

Empirical: a(n) = 4*a(n-1) +137*a(n-2) -560*a(n-3) -8456*a(n-4) +35504*a(n-5) +310702*a(n-6) -1349320*a(n-7) -7561533*a(n-8) +34294092*a(n-9) +128206281*a(n-10) -615707400*a(n-11) -1548288698*a(n-12) +8040276992*a(n-13) +13333179376*a(n-14) -77453548480*a(n-15) -79946374816*a(n-16) +552146144704*a(n-17) +309222145232*a(n-18) -2893327015040*a(n-19) -567224779296*a(n-20) +10948880162304*a(n-21) -974085452928*a(n-22) -28950298675200*a(n-23) +9103597862400*a(n-24) +50436504576000*a(n-25) -24908850432000*a(n-26) -51674112000000*a(n-27) +32903055360000*a(n-28) +23410114560000*a(n-29) -17557585920000*a(n-30).

Example

Some solutions for n=3:
  1 5 1 6 1      6 6 6 6 5      4 0 5 1 5      7 1 4 1 6
  4 1 4 2 4      7 0 7 0 6      0 3 1 4 1      4 5 1 5 3
  1 5 1 6 1      1 1 1 1 0      6 2 7 3 7      6 0 3 0 5
  3 0 3 1 3      7 0 7 0 6      3 6 4 7 4      3 4 0 4 2

Crossrefs

Column 4 of A234728.

Sequence in context: A261748 A089522 A251041 * A237554 A263024 A367650

Adjacent sequences: A234721 A234722 A234723 * A234725 A234726 A234727

Keyword

nonn

Author

R. H. Hardin, Dec 30 2013

Status

approved