A184010 n + floor(sqrt(-1+4n/3)); complement of A001859 (except for initial zero).

1, 3, 4, 6, 7, 8, 9, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 103, 104, 105, 106, 107, 108, 109, 110, 111

Offset

1,2

Links

Table of n, a(n) for n=1..100.

Formula

a(n) = n + floor(sqrt(-1+4n/3))

Mathematica

  a=4/3; b=-1; Table[n+Floor[(a*n+b)^(1/2)], {n, 100}]

Crossrefs

Cf. A001859.

Sequence in context: A080804 A164386 A111909 * A256827 A175139 A182835

Adjacent sequences: A184007 A184008 A184009 * A184011 A184012 A184013

Keyword

nonn,easy

Author

Clark Kimberling, Jan 08 2011

Status

approved