A183860 a(n) = n+floor(sqrt(3n+1)); complement of A183861.

3, 4, 6, 7, 9, 10, 11, 13, 14, 15, 16, 18, 19, 20, 21, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 67, 69, 70, 71, 72, 73, 74, 75, 76, 77, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 101, 102, 103, 104, 105, 106

Offset

1,1

Links

Table of n, a(n) for n=1..90.

Formula

a(n)=n+floor(sqrt(3n+1)).

Mathematica

a=3; b=1;
Table[n+Floor[(a*n+b)^(1/2)], {n, 90}] (* A183860 *)
Table[n-1+Ceiling[(n*n-b)/a], {n, 70}] (* A183861 *)

Prog

(PARI) a(n) = n + sqrtint(3*n+1); \\ Michel Marcus, Jul 13 2022

Crossrefs

Cf. A183861.

Sequence in context: A070762 A061208 A325439 * A298109 A184429 A248185

Adjacent sequences: A183857 A183858 A183859 * A183861 A183862 A183863

Keyword

nonn,easy

Author

Clark Kimberling, Jan 07 2011

Status

approved