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A220635 Number of ways to reciprocally link elements of an 5Xn array either to themselves or to exactly two horizontal or antidiagonal neighbors 1
1, 1, 8, 114, 1481, 17527, 201903, 2329448, 26904225, 310837917, 3591561452, 41499180881, 479508472309, 5540546671074, 64018957168901, 739714921940047, 8547125318062702, 98758781455779205, 1141120102778497151 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Row 5 of A220632

LINKS

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

FORMULA

Empirical: a(n) = 16*a(n-1) -39*a(n-2) -186*a(n-3) +419*a(n-4) +1024*a(n-5) -1049*a(n-6) -2258*a(n-7) +861*a(n-8) +2000*a(n-9) -133*a(n-10) -586*a(n-11) -16*a(n-12) +32*a(n-13) for n>17

EXAMPLE

Some solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10)

.00.67.47...00.67.47...00.00.00...00.00.00...00.00.00...00.67.47...00.00.00

.36.34.00...36.34.00...00.00.00...00.67.47...00.67.47...36.34.00...00.00.00

.00.67.47...00.00.00...00.00.00...36.34.00...36.34.00...00.00.00...00.00.00

.36.34.00...00.67.47...00.67.47...00.67.47...00.00.00...00.00.00...00.00.00

.00.00.00...36.34.00...36.34.00...36.34.00...00.00.00...00.00.00...00.00.00

CROSSREFS

Sequence in context: A217772 A062126 A222520 * A113670 A156468 A293992

Adjacent sequences:  A220632 A220633 A220634 * A220636 A220637 A220638

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 17 2012

STATUS

approved

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Last modified May 16 21:59 EDT 2021. Contains 343954 sequences. (Running on oeis4.)