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!)
 A212825 Number of 0..4 arrays of length n with no adjacent pair equal to its immediately preceding adjacent pair, and new values introduced in 0..4 order. 1
 1, 2, 5, 13, 44, 167, 695, 3070, 14074, 65958, 313098, 1497216, 7189646, 34606966, 166803484, 804596882, 3882748894, 18741593296, 90476092366, 436812623774, 2108996095916, 10182801139146, 49166003981046, 237391983175872 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 4 of A212829. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 7*a(n-1) - 7*a(n-2) - 20*a(n-3) + 10*a(n-4) + 24*a(n-5) + 8*a(n-6) for n>9. Empirical g.f.: x*(1 + x + x^2)*(1 - 6*x + 3*x^2 + 15*x^3 - 9*x^5 - 3*x^6) / ((1 - x - x^2)*(1 - 2*x - 2*x^2)*(1 - 4*x - 4*x^2)). - Colin Barker, Jul 21 2018 EXAMPLE Some solutions for n=8: ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0 ..1....1....1....1....1....1....0....1....1....0....1....1....1....1....1....1 ..2....2....2....2....2....2....1....2....2....1....2....2....0....0....1....1 ..3....1....3....1....2....0....2....3....2....0....1....3....2....2....0....2 ..4....0....0....1....0....3....2....1....0....2....1....2....0....0....1....2 ..3....2....0....2....2....4....1....1....0....0....1....1....0....3....2....1 ..0....2....2....2....2....2....0....0....1....3....3....1....2....1....3....2 ..4....2....0....2....0....1....1....2....3....4....3....2....3....0....4....3 CROSSREFS Cf. A212829. Sequence in context: A287008 A119533 A066740 * A212826 A212827 A212828 Adjacent sequences:  A212822 A212823 A212824 * A212826 A212827 A212828 KEYWORD nonn AUTHOR R. H. Hardin, May 28 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 January 26 17:34 EST 2020. Contains 331280 sequences. (Running on oeis4.)