The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A220715 Number of ways to reciprocally link elements of an nX4 array either to themselves or to exactly two king-move neighbors, without consecutive collinear links 1
 1, 118, 2243, 72923, 2126423, 63806966, 1902974315, 56814065240, 1695753689937, 50616199772781, 1510818091855523, 45095791460540255, 1346044870553900218, 40177524253586319614, 1199241822560808863212, 35795659984527447229283 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 4 of A220718 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 27*a(n-1) +218*a(n-2) -4167*a(n-3) -2238*a(n-4) +279765*a(n-5) -837556*a(n-6) -9510069*a(n-7) +51706001*a(n-8) +170902685*a(n-9) -1379270603*a(n-10) -2916930858*a(n-11) +23871214217*a(n-12) +48592745276*a(n-13) -298839593926*a(n-14) -429563948989*a(n-15) +2118042013180*a(n-16) +3879992721463*a(n-17) -18932568794516*a(n-18) +5172886486038*a(n-19) +48756445038822*a(n-20) +9597136541026*a(n-21) -41796254756289*a(n-22) -896030877308524*a(n-23) +1207224499666967*a(n-24) +3111135194463020*a(n-25) -1604076203019642*a(n-26) -15273373653497609*a(n-27) -10825292853008442*a(n-28) +81352919819320477*a(n-29) +34933338667422793*a(n-30) -143384540350983525*a(n-31) -385018692637254330*a(n-32) +308969134164070030*a(n-33) +1717971050198499504*a(n-34) -1564322409532992905*a(n-35) -2986300709023877703*a(n-36) +2110252700439366942*a(n-37) +5453780366327497679*a(n-38) +371316710789284744*a(n-39) -14266820049835803870*a(n-40) +821793489703620010*a(n-41) +20101913038833494061*a(n-42) -126600521568603311*a(n-43) -21586493455386361844*a(n-44) -2133427856527889127*a(n-45) +19425074896572483723*a(n-46) +2217428671242118766*a(n-47) -13966094878768033977*a(n-48) +1438576255704793871*a(n-49) +4174978235974982028*a(n-50) +1538080869042294965*a(n-51) -17129837797868140650*a(n-52) +32360333812276354278*a(n-53) -9761802512302820845*a(n-54) -37046343187525306954*a(n-55) +38590238998125051624*a(n-56) -10645213180052535365*a(n-57) +19247049676319604348*a(n-58) -30460679562886114932*a(n-59) +11473284550788820469*a(n-60) +2653613573023586974*a(n-61) -2845704340430549512*a(n-62) +2351965695570937626*a(n-63) -3994448694896953184*a(n-64) +3426390086734421544*a(n-65) -1570449846470389084*a(n-66) +1687013684172456220*a(n-67) -767997366767314992*a(n-68) -171849877273372592*a(n-69) +13888647368350704*a(n-70) -68870557102727648*a(n-71) +126980968396773696*a(n-72) -98731887707797568*a(n-73) +50215450311674752*a(n-74) -9026127145861376*a(n-75) +1020535271492608*a(n-76) -280997983232000*a(n-77) -57798187278336*a(n-78) -16904717058048*a(n-79) +14172273278976*a(n-80) -957233561600*a(n-81) -80442294272*a(n-82) -811597824*a(n-83) EXAMPLE Some solutions for n=3 0=self 1=nw 2=n 3=ne 4=w 6=e 7=sw 8=s 9=se (reciprocal directions total 10) .69.48.89.00...89.00.89.00...00.00.69.47...69.47.00.00...00.00.69.47 .00.12.26.14...29.18.29.18...89.00.38.18...38.18.68.47...89.78.36.14 .00.00.00.00...00.12.00.12...26.14.26.24...26.24.23.00...23.12.00.00 CROSSREFS Sequence in context: A334646 A232776 A175876 * A230917 A230248 A263954 Adjacent sequences:  A220712 A220713 A220714 * A220716 A220717 A220718 KEYWORD nonn AUTHOR R. H. Hardin Dec 18 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 30 17:12 EST 2021. Contains 349424 sequences. (Running on oeis4.)