A283775 Numbers k such that floor(k*sqrt(3)) is even.

4, 5, 6, 7, 12, 13, 14, 19, 20, 21, 22, 27, 28, 29, 34, 35, 36, 37, 42, 43, 44, 49, 50, 51, 52, 56, 57, 58, 59, 64, 65, 66, 67, 71, 72, 73, 74, 79, 80, 81, 82, 86, 87, 88, 89, 94, 95, 96, 97, 101, 102, 103, 104, 109, 110, 111, 116, 117, 118, 119, 124, 125, 126

Offset

1,1

Comments

Complement of A283776.

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Formula

a(n+1) - a(n) is in {1,4,5} for every n.

Mathematica

r = Sqrt[3]; z = 350; t = Table[Floor[n*r], {n, 1, z}]; u = Mod[t, 2];
Flatten[Position[u, 0]]  (* A283775 *)
Flatten[Position[u, 1]]  (* A283776 *)

Prog

(PARI) for(n=1, 130, if(sqrtint(3*n^2)%2==0, print1(n, ", "))) \\ Indranil Ghosh, Mar 21 2017
(Python)
from math import isqrt
print([n for n in range(1, 130) if isqrt(3*n**2)%2==0]) # Indranil Ghosh, Mar 21 2017

Crossrefs

Cf. A002194, A283776.

Sequence in context: A086101 A131260 A047566 * A037355 A294228 A342575

Adjacent sequences: A283772 A283773 A283774 * A283776 A283777 A283778

Keyword

nonn,easy

Author

Clark Kimberling, Mar 19 2017

Status

approved