This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A245487 Number of compositions of n into parts 3,4 where both parts are always present. 5
 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 3, 3, 0, 4, 6, 4, 5, 10, 10, 11, 15, 20, 22, 27, 35, 43, 49, 63, 79, 92, 112, 144, 171, 204, 257, 316, 375, 462, 573, 692, 838, 1035, 1265, 1532, 1873, 2300, 2798, 3406, 4173, 5099, 6204, 7580, 9273, 11303, 13784, 16855, 20576 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (-1,-1,1,3,3,2,-1,-2,-2,-1). FORMULA a(n) = a(n-3)+a(n-4)+b(n) where b(n) is the 12-cycle (1,0,1,0,1,1,0,0,2,0,0,1) starting with initial value b(11)=1 and b(n)=b(n-12) e.g. b(23)=b(11). The initial values for a(n) are a(7)=2,a(8)=0,a(9)=0,a(10)=3. G.f.: x^7*(x^3+2*x^2+2*x+2) / ((x-1)*(x+1)*(x^2+1)*(x^2+x+1)*(x^4+x^3-1)). - Colin Barker, Jul 24 2014 EXAMPLE a(16)=5, the compositions being 43333, 34333, 33433, 33343, 33334. MATHEMATICA CoefficientList[Series[x^7 (x^3 + 2 x^2 + 2 x + 2)/((x - 1) (x + 1) (x^2 + 1) (x^2 + x + 1) * (x^4 + x^3 - 1)), {x, 0, 60}], x] (* Vincenzo Librandi, Jul 25 2014 *) PROG (PARI) a=[0, 0, 0, 0, 0, 0, 2, 0, 0, 3]; b=[1, 0, 1, 0, 1, 1, 0, 0, 2, 0, 0, 1]; k=1; for(n=11, 100, a=concat(a, a[n-3]+a[n-4]+b[k]); if(k==#b, k=1, k++)); a \\ Colin Barker, Jul 24 2014 CROSSREFS Cf. A245332. Sequence in context: A188122 A050186 A278094 * A074734 A174956 A124182 Adjacent sequences:  A245484 A245485 A245486 * A245488 A245489 A245490 KEYWORD nonn,easy AUTHOR David Neil McGrath, Jul 23 2014 EXTENSIONS More terms from Colin Barker, Jul 24 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 16 00:33 EST 2019. Contains 330013 sequences. (Running on oeis4.)