A203654 1/25 the number of (n+1)X7 0..4 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements

531441, 178019197, 71156938905, 30292030417413, 13192335511091073, 5796397762880763341, 2554890395768832271017, 1127594169687376371159253, 497870086469175871336506385, 219871060492143544799371582749

Offset

1,1

Comments

Column 6 of A203656

Links

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

Formula

Empirical: a(n) = 329*a(n-1) +107668*a(n-2) -25063968*a(n-3) -680298432*a(n-4) +202122434560*a(n-5) +566048790528*a(n-6) -556012878114816*a(n-7) +3504577252474880*a(n-8) +591608256378830848*a(n-9) -6839009506476949504*a(n-10) -239163894638688862208*a(n-11) +3525511542366864932864*a(n-12) +35450315597944711020544*a(n-13) -664062013074729355706368*a(n-14) -1530140375300205031981056*a(n-15) +50183396342386988796608512*a(n-16) -17094562720050709209808896*a(n-17) -1622789056358547469740539904*a(n-18) +2031702560273665184466206720*a(n-19) +21489007078579909036995510272*a(n-20) -30394434853378035268349591552*a(n-21) -101547952483445807369349496832*a(n-22) +114461568017537120233548939264*a(n-23) +177927593591172462047265816576*a(n-24) -114513709337590944825725681664*a(n-25) -72325116345546289517124648960*a(n-26) +34013569597018368539319336960*a(n-27) -3061173118029560521791897600*a(n-28)

Example

Some solutions for n=4
..4..2..4..2..4..1..1....0..4..4..2..4..3..0....0..0..0..2..1..1..2
..1..4..4..4..2..4..1....3..0..4..4..4..4..3....1..0..3..0..2..1..1
..0..1..4..3..4..2..4....3..3..0..4..0..4..4....3..1..0..0..0..2..1
..4..0..1..4..0..4..4....0..3..3..0..2..0..4....1..4..1..0..0..0..2
..2..4..0..1..4..1..4....0..0..3..3..0..4..3....4..2..4..1..0..3..0

Crossrefs

Sequence in context: A017382 A017502 A017634 * A016764 A016776 A016848

Adjacent sequences: A203651 A203652 A203653 * A203655 A203656 A203657

Keyword

nonn

Author

R. H. Hardin Jan 04 2012

Status

approved