A111652 3n appears n times.

3, 6, 6, 9, 9, 9, 12, 12, 12, 12, 15, 15, 15, 15, 15, 18, 18, 18, 18, 18, 18, 21, 21, 21, 21, 21, 21, 21, 24, 24, 24, 24, 24, 24, 24, 24, 27, 27, 27, 27, 27, 27, 27, 27, 27, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 36, 36, 36, 36, 36

Offset

1,1

Links

Table of n, a(n) for n=1..71.

Formula

a(n) = 3*A002024(n) = A111650(n)*3/2. - Chai Wah Wu, Jun 06 2025

Mathematica

Flatten[Table[Table[3n, {n}], {n, 15}]] (* Harvey P. Dale, Jul 23 2013 *)

Prog

(Python)
from math import isqrt
def A111652(n): return (m:=isqrt(n<<3)+1&-2)+(m>>1) # Chai Wah Wu, Jun 06 2025

Crossrefs

Cf. A000194, A008585, A111650, A111651, A002024.

Sequence in context: A147866 A135702 A108850 * A159787 A184161 A276000

Adjacent sequences: A111649 A111650 A111651 * A111653 A111654 A111655

Keyword

easy,nonn

Author

Jonathan Vos Post, Aug 12 2005

Status

approved