The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A245868 Number of length n+2 0..7 arrays with some pair in every consecutive three terms totalling exactly 7. 1
 168, 712, 2368, 8840, 31176, 113024, 404264, 1455496, 5223552, 18775816, 67437448, 242306240, 870461352, 3127322696, 11235107264, 40363689352, 145010699592, 520968428032, 1871637364264, 6724074597128, 24157004951808, 86786820122120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 Robert Israel, Maple-assisted derivation of recurrence FORMULA Empirical: a(n) = 2*a(n-1) + 6*a(n-2) - a(n-3). Empirical g.f.: 8*x*(21 + 47*x - 8*x^2) / (1 - 2*x - 6*x^2 + x^3). - Colin Barker, Nov 04 2018 Empirical recurrence verified: see link. - Robert Israel, May 13 2020 EXAMPLE Some solutions for n=6: ..4....6....7....0....7....3....6....4....0....2....6....1....6....5....0....2 ..2....4....6....0....2....6....3....5....7....6....0....7....6....6....7....5 ..3....3....1....7....0....1....4....2....6....1....1....0....1....2....6....6 ..5....6....4....4....5....6....0....6....1....1....6....1....1....1....0....1 ..2....1....3....0....2....5....7....5....0....6....7....6....6....6....7....7 ..4....6....4....3....4....2....2....2....7....1....0....6....7....7....2....6 ..5....3....3....4....3....5....5....0....5....1....7....1....0....0....5....1 ..2....4....2....3....2....4....6....5....2....6....0....2....2....6....3....7 CROSSREFS Column 7 of A245869. Sequence in context: A157998 A234823 A234816 * A251461 A110285 A302887 Adjacent sequences: A245865 A245866 A245867 * A245869 A245870 A245871 KEYWORD nonn AUTHOR R. H. Hardin, Aug 04 2014 STATUS approved

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

Last modified June 7 21:29 EDT 2023. Contains 363157 sequences. (Running on oeis4.)