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A220723 Number of ways to reciprocally link elements of an nX6 array either to themselves or to exactly two horizontal, diagonal or antidiagonal neighbors 1
1, 221, 14466, 1071230, 78144195, 5717794568, 418227762771, 30590627951201, 2237516237251959, 163660666377014852, 11970779327114888365, 875589432986745821505, 64044022151487396268429, 4684429285176288596665322 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 6 of A220725

LINKS

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

FORMULA

Empirical: a(n) = 45*a(n-1) +1582*a(n-2) +28001*a(n-3) +433541*a(n-4) +4651620*a(n-5) +23050514*a(n-6) +19068768*a(n-7) -406768923*a(n-8) -5454363966*a(n-9) -21368732877*a(n-10) -43423709350*a(n-11) -115165374878*a(n-12) +756870881518*a(n-13) -509592403258*a(n-14) +2771092501395*a(n-15) +45532332417169*a(n-16) +84268947801729*a(n-17) +197680566318162*a(n-18) +526864500717518*a(n-19) -496199604227766*a(n-20) -3172876334966285*a(n-21) -18518543377735367*a(n-22) -34421434014178193*a(n-23) -24661869350348541*a(n-24) +35289378475373241*a(n-25) +311480084475722358*a(n-26) +348944504565667849*a(n-27) +294809682317936264*a(n-28) -401624452647533343*a(n-29) -1074075405271555698*a(n-30) -1213035070902387124*a(n-31) -399539817910569697*a(n-32) +228994070464622673*a(n-33) +6068818810350980741*a(n-34) -5789263051729837258*a(n-35) +9345835665171867909*a(n-36) -17672770293093347361*a(n-37) +17987389975766461436*a(n-38) -13443505741571016037*a(n-39) +6307663990736093524*a(n-40) +1434716781628827769*a(n-41) -7776478558306473077*a(n-42) +6796633653830672142*a(n-43) -4481387637284166371*a(n-44) +6238840842311948673*a(n-45) -4550183890456117078*a(n-46) +3369124264335866193*a(n-47) -1949697096103324912*a(n-48) -1063973984730200467*a(n-49) +879696446535891482*a(n-50) -451385404187929054*a(n-51) +920333305675824074*a(n-52) -604577992143490665*a(n-53) +367729328375441160*a(n-54) -117763190367582785*a(n-55) -12809673386068969*a(n-56) +20235039760005972*a(n-57) -89066787672812435*a(n-58) +58180674130630065*a(n-59) -8092929420115408*a(n-60) +11767600444786911*a(n-61) -3105966336514588*a(n-62) -3508066162395757*a(n-63) +140346369067488*a(n-64) -571536988020730*a(n-65) +743552379111436*a(n-66) -147965089387860*a(n-67) +116202723919906*a(n-68) -4981534037567*a(n-69) -44993398290417*a(n-70) +9440477072358*a(n-71) -381157593992*a(n-72) -40176472548*a(n-73) +696703951996*a(n-74) -124278496514*a(n-75) -42464507420*a(n-76) +2583880728*a(n-77) -646911128*a(n-78) +691595746*a(n-79) +100700185*a(n-80) -37331595*a(n-81) +2989871*a(n-82) -712174*a(n-83) -351495*a(n-84) +98364*a(n-85) +6384*a(n-86) -2584*a(n-87) +28*a(n-88) +22*a(n-89) -a(n-90)

EXAMPLE

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

.00.67.46.49.00.00...00.69.46.49.79.00...69.49.69.47.00.00...69.47.00.00.79.00

.36.47.00.67.14.00...00.79.16.34.17.17...69.14.13.16.49.00...36.14.00.39.00.17

.36.46.34.00.00.00...36.46.14.36.34.00...00.16.46.46.46.14...00.00.00.00.13.00

CROSSREFS

Sequence in context: A177422 A177420 A220737 * A011816 A048902 A210135

Adjacent sequences:  A220720 A220721 A220722 * A220724 A220725 A220726

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 18 2012

STATUS

approved

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Last modified September 27 20:35 EDT 2020. Contains 337388 sequences. (Running on oeis4.)