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!)
 A214272 Number of compositions of n where the difference between largest and smallest parts equals 3 and adjacent parts are unequal. 2
 0, 2, 1, 8, 12, 18, 46, 69, 111, 208, 340, 539, 910, 1497, 2403, 3924, 6331, 10230, 16531, 26591, 42652, 68595, 110195, 176458, 282895, 452990, 725036, 1160067, 1855376, 2966265, 4740385, 7574822, 12099506, 19324253, 30856321, 49260709, 78631609, 125495919 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,2 LINKS Alois P. Heinz, Table of n, a(n) for n = 4..2000 FORMULA a(n) ~ c * d^n, where d = 1.59406371344091594038982448... is the root of the equation -3 + d - 3*d^2 - 3*d^4 + d^5 - 2*d^6 + d^7 - d^8 + d^9 = 0, and c = 0.63168955798354197444724247228159886565558573072349896252... . - Vaclav Kotesovec, Sep 01 2014 EXAMPLE T(5) = 2: [4,1], [1,4]. T(6) = 1: [1,4,1]. T(7) = 8: [5,2], [4,2,1], [4,1,2], [2,5], [2,4,1], [2,1,4], [1,4,2], [1,2,4]. T(8) = 12: [4,3,1], [4,1,3], [4,1,2,1], [3,4,1], [3,1,4], [2,1,4,1], [1,4,3], [1,4,2,1], [1,4,1,2], [1,3,4], [1,2,4,1], [1,2,1,4]. CROSSREFS Column k=3 of A214269. Sequence in context: A118708 A055134 A137370 * A214273 A214274 A214275 Adjacent sequences:  A214269 A214270 A214271 * A214273 A214274 A214275 KEYWORD nonn AUTHOR Alois P. Heinz, Jul 09 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 September 23 11:53 EDT 2020. Contains 337310 sequences. (Running on oeis4.)