This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A248960 Number of ternary words of length n in which all digits 0..2 occur in every 5 consecutive digits. 2
 1, 3, 9, 27, 81, 150, 366, 870, 2022, 4686, 10974, 25614, 59742, 139398, 325350, 759198, 1771590, 4134126, 9647262, 22512342, 52533750, 122590422, 286071414, 667563054, 1557794622, 3635198310, 8482932318, 19795382454, 46193598486, 107795266974, 251546100558, 586996465758, 1369788083022 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Colin Barker, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (1,2,2,2,-1,-1). FORMULA G.f.: (1+2*x+4*x^2+10*x^3+28*x^4-8*x^5-14*x^6-6*x^8+3*x^10) / ((1+x)*(1-2*x-2*x^3+x^5)). - Colin Barker, Oct 27 2016 a(n) = a(n-1) + 2*a(n-2) + 2*a(n-3) + 2*a(n-4) - a(n-5) - a(n-6). a(n) = A242317(n-4) * 6. MATHEMATICA Join[{1, 3, 9, 27, 81}, LinearRecurrence[{1, 2, 2, 2, -1, -1}, {150, 366, 870, 2022, 4686, 10974}, 30]] (* Harvey P. Dale, Apr 04 2015 *) PROG (PARI) Vec((1+2*x+4*x^2+10*x^3+28*x^4-8*x^5-14*x^6-6*x^8+3*x^10)/((1+x)*(1-2*x-2*x^3+x^5)) + O(x^30)) \\ Colin Barker, Oct 27 2016 CROSSREFS Cf. A242317, A249019. Sequence in context: A014950 A271351 A036143 * A006521 A289257 A014953 Adjacent sequences:  A248957 A248958 A248959 * A248961 A248962 A248963 KEYWORD nonn,easy AUTHOR Andrew Woods, Jan 12 2015 EXTENSIONS Changed offset to 0. - N. J. A. Sloane, Jan 15 2015 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 April 20 16:17 EDT 2019. Contains 322310 sequences. (Running on oeis4.)