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A187327
a(n) = floor(n/5) + floor(2n/5) + floor(3n/5).
0
0, 0, 1, 2, 3, 6, 6, 7, 8, 9, 12, 12, 13, 14, 15, 18, 18, 19, 20, 21, 24, 24, 25, 26, 27, 30, 30, 31, 32, 33, 36, 36, 37, 38, 39, 42, 42, 43, 44, 45, 48, 48, 49, 50, 51, 54, 54, 55, 56, 57, 60, 60, 61, 62, 63, 66, 66, 67, 68, 69, 72, 72, 73, 74, 75, 78, 78, 79, 80, 81, 84, 84, 85, 86, 87, 90, 90, 91, 92, 93, 96, 96, 97, 98, 99, 102, 102, 103, 104, 105, 108, 108, 109, 110, 111, 114, 114, 115, 116, 117, 120, 120, 121, 122, 123, 126, 126, 127, 128, 129, 132, 132, 133, 134, 135, 138, 138, 139, 140, 141, 144
OFFSET
0,4
FORMULA
a(n) = floor(n/5)+floor(2n/5)+floor(3n/5).
a(n)= +a(n-1) +a(n-5) -a(n-6). G.f. ( x^4*(1+x+x^2+3*x^3) ) / ( (x^4+x^3+x^2+x+1)*(x-1)^2 ). - R. J. Mathar, Mar 18 2011
MATHEMATICA
Table[Floor[n/5]+Floor[2n/5]+Floor[3n/5], {n, 0, 120}]
LinearRecurrence[{1, 0, 0, 0, 1, -1}, {0, 0, 1, 2, 3, 6}, 130] (* Harvey P. Dale, Sep 26 2016 *)
PROG
(PARI) a(n)=n\5+2*n\5+3*n\5 \\ Charles R Greathouse IV, Mar 17 2011
CROSSREFS
Sequence in context: A333936 A193896 A099162 * A271716 A362706 A220178
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Mar 08 2011
STATUS
approved