This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A187331 a(n) = Sum_{k=1..4} floor(k*n/4). 2
 0, 1, 4, 6, 10, 11, 14, 16, 20, 21, 24, 26, 30, 31, 34, 36, 40, 41, 44, 46, 50, 51, 54, 56, 60, 61, 64, 66, 70, 71, 74, 76, 80, 81, 84, 86, 90, 91, 94, 96, 100, 101, 104, 106, 110, 111, 114, 116, 120, 121, 124, 126, 130, 131, 134, 136, 140, 141, 144, 146, 150, 151, 154, 156, 160, 161, 164 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS M. F. Hasler, Table of n, a(n) for n = 0..1000 FORMULA From Chai Wah Wu, Jun 07 2016: (Start) a(n) = a(n-1) + a(n-4) - a(n-5) for n > 4. G.f.: x*(4*x^3 + 2*x^2 + 3*x + 1)/(x^5 - x^4 - x + 1). (End) a(n) = n + A187326(n), where A187326(n) = [n/4] + [n/2] + [3n/4], [.] = floor. - M. F. Hasler, Nov 21 2017 MATHEMATICA t=Table[Sum[Floor[k*n/4], {k, 1, 4}], {n, 0, 200}]  (* A187331 *) Complement[Range[Length[t]], t]                (* A187332 *) PROG (PARI) A187331(n)=n\4+n\2+3*n\4+n \\ M. F. Hasler, Nov 21 2017 CROSSREFS Cf. A187332 (complement), A187326 (= a(n) - n), A187333. Sequence in context: A185002 A110604 A109270 * A184923 A137877 A246022 Adjacent sequences:  A187328 A187329 A187330 * A187332 A187333 A187334 KEYWORD nonn AUTHOR Clark Kimberling, Mar 08 2011 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 August 18 04:50 EDT 2019. Contains 326072 sequences. (Running on oeis4.)