A385704 Complement of A184535.

3, 4, 6, 7, 8, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 37, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78

Offset

1,1

Comments

Numbers > 1 not of the form floor(3*k^2/5).

Links

Table of n, a(n) for n=1..67.

Formula

a(n) = n+m+1 if n+m>=floor(3*(m+1)^2/5) and a(n) = n+m otherwise where m = floor(sqrt(5*n/3)).

Mathematica

m[n_]:=Floor[Sqrt[5n/3]]; a[n_]:=If[n+m[n]>=Floor[3(m[n]+1)^2/5], n+m[n]+1, n+m[n]]; Array[a, 67] (* James C. McMahon, Aug 06 2025 *)

Prog

(Python)
from math import isqrt
def A385704(n): return n+(m:=isqrt(5*n//3))+(n+m>=3*(m+1)**2//5)

Crossrefs

Cf. A184535.

Sequence in context: A298644 A075747 A143344 * A007401 A275481 A234349

Adjacent sequences: A385701 A385702 A385703 * A385705 A385706 A385707

Keyword

nonn,easy

Author

Chai Wah Wu, Aug 04 2025

Status

approved