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A220729 Number of ways to reciprocally link elements of an 5Xn array either to themselves or to exactly two horizontal, diagonal or antidiagonal neighbors 1
1, 16, 534, 29310, 1485872, 78144195, 4067687187, 212706905400, 11106137334222, 580235608693971, 30307625049945769, 1583199541947366392, 82700087992036283508, 4319976719534879507298, 225660175403712971157580 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 5 of A220725

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..180

FORMULA

Empirical: a(n) = 32*a(n-1) +1264*a(n-2) -6328*a(n-3) -241310*a(n-4) +146565*a(n-5) +12166959*a(n-6) +2497325*a(n-7) -202170319*a(n-8) +1848259852*a(n-9) +6416504248*a(n-10) -135895446570*a(n-11) -289784605504*a(n-12) +3768170929588*a(n-13) +5368204739821*a(n-14) -54471772414739*a(n-15) -38572226199359*a(n-16) +461349410402753*a(n-17) -24739259532414*a(n-18) -2337088216780713*a(n-19) +2005903218882750*a(n-20) +6641872665507706*a(n-21) -10922605376031085*a(n-22) -10978333007238715*a(n-23) +29077522138037087*a(n-24) +6193925205936189*a(n-25) -81042115937846656*a(n-26) +48012246065697135*a(n-27) +230477178606012294*a(n-28) -71100222285119909*a(n-29) -484564106783138657*a(n-30) +63397519256525597*a(n-31) +317113017188010612*a(n-32) +208284692511325843*a(n-33) -36848833376106522*a(n-34) -314060732036714070*a(n-35) -338239148421413922*a(n-36) +419219103653941844*a(n-37) +28280400298537090*a(n-38) +16410882790249086*a(n-39) -21566776250365534*a(n-40) -63152569911326562*a(n-41) +53387728048987481*a(n-42) +1662797378595523*a(n-43) -78423964581496985*a(n-44) +22065278508797304*a(n-45) +21776123593901432*a(n-46) -7350137282745121*a(n-47) -1550346580925857*a(n-48) +4812867903452636*a(n-49) -1789798309320559*a(n-50) -447270770509596*a(n-51) +252097304903520*a(n-52) -51793570711282*a(n-53) +7515111076940*a(n-54) +3182418991486*a(n-55) -893589945132*a(n-56) +121859858544*a(n-57) +28232899872*a(n-58) -1644238464*a(n-59) +172846080*a(n-60)

EXAMPLE

Some solutions for n=3 0=self 1=nw 3=ne 4=w 6=e 7=sw 9=se (reciprocal directions total 10)

.00.00.00...69.46.47...00.79.00...00.79.00...00.00.00...00.00.00...00.67.47

.00.79.00...00.13.00...39.79.17...36.46.14...00.79.00...69.49.00...36.34.00

.39.67.14...69.47.00...39.13.17...00.67.47...36.47.17...00.17.17...00.69.47

.36.14.00...36.14.00...00.13.00...36.34.00...39.37.00...39.36.47...69.34.17

.00.00.00...00.00.00...00.00.00...00.00.00...36.14.00...00.13.00...00.13.00

CROSSREFS

Sequence in context: A263907 A222099 A254126 * A196298 A274136 A187160

Adjacent sequences:  A220726 A220727 A220728 * A220730 A220731 A220732

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 18 2012

STATUS

approved

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Last modified September 22 05:11 EDT 2021. Contains 347605 sequences. (Running on oeis4.)