A183679 Number of (n+1) X 7 0..7 arrays with every 2 X 2 subblock summing to 14.

4497760, 12267368, 40112416, 149494472, 614337760, 2724755048, 12852639136, 63792013832, 330496651360, 1776260495528, 9855139668256, 56224667870792, 328776237883360, 1965267909208808, 11981572266095776, 74361042869065352, 469032697930065760, 3002404748555630888, 19480778982683377696

Offset

1,1

Links

Paolo Xausa, Table of n, a(n) for n = 1..1000

Christian Krause, Proof of formula, Jun 13 2026

Formula

a(n) = 8*8^n + 882*7^n + 11592*6^n + 60690*5^n + 190176*4^n + 420210*3^n + 683592*2^n + 730002. - Christian Krause, Jun 13 2026

Example

Some solutions for 3 X 7:
..4..6..6..1..4..4..6....2..2..4..2..3..5..3....4..6..0..7..1..6..4
..2..2..0..7..2..4..0....6..4..4..4..5..1..5....0..4..4..3..3..4..0
..4..6..6..1..4..4..6....2..2..4..2..3..5..3....6..4..2..5..3..4..6

Mathematica

A183679[n_] := 8*8^n + 882*7^n + 11592*6^n + 60690*5^n + 190176*4^n + 420210*3^n + 683592*2^n + 730002;
Array[A183679, 25] (* Paolo Xausa, Jun 16 2026 *)

Crossrefs

Column 6 of A183680.

Sequence in context: A339536 A319064 A344831 * A234793 A227040 A227039

Adjacent sequences: A183676 A183677 A183678 * A183680 A183681 A183682

Keyword

nonn,easy,changed

Author

R. H. Hardin, Jan 06 2011

Extensions

a(6)-a(19) from Christian Krause, Jun 13 2026

Status

approved