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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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

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