This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A275908 Expansion of (1+2*x+4*x^2+4*x^3+6*x^4+4*x^5+x^6) / (1-3*x-x^2-6*x^3-7*x^4-7*x^5-5*x^6-x^7). 1
 1, 5, 20, 75, 288, 1105, 4234, 16226, 62188, 238340, 913452, 3500857, 13417236, 51422337, 197079099, 755317101, 2894796675, 11094476468, 42520225774, 162961236161, 624558407329, 2393656389397, 9173827208656, 35159225871899, 134749776270503, 516436347919005, 1979272313718089 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Colin Barker, Table of n, a(n) for n = 0..1000 T. Doslic, T. Short, Maximal matchings in polyspiro and benzenoid chains, arXiv:1511.00590, [math.CO], 2015. See Th. 4.4. Index entries for linear recurrences with constant coefficients, signature (3,1,6,7,7,5,1). FORMULA a(n) = 3*a(n-1)+a(n-2)+6*a(n-3)+7*a(n-4)+7*a(n-5)+5*a(n-6)+a(n-7) for n>6. - Colin Barker, Aug 26 2016 PROG (PARI) Vec((1+2*x+4*x^2+4*x^3+6*x^4+4*x^5+x^6)/(1-3*x-x^2-6*x^3-7*x^4-7*x^5-5*x^6-x^7) + O(x^30)) \\ Colin Barker, Aug 26 2016 CROSSREFS Sequence in context: A000344 A290922 A275909 * A290909 A270023 A061278 Adjacent sequences:  A275905 A275906 A275907 * A275909 A275910 A275911 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Aug 26 2016 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 23 01:24 EDT 2018. Contains 316518 sequences. (Running on oeis4.)