A220729 - OEIS

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, 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: A222099 A362520 A254126 * A196298 A361310 A274136

Adjacent sequences: A220726 A220727 A220728 * A220730 A220731 A220732

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 18 2012

STATUS

approved