A133196 n+2 repeated n times.

3, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15

Offset: 1

Author

Paul Curtz, Oct 09 2007

Keywords

• nonn

Crossrefs

Cf. A002024, A003056, A003057.

Programs

Mathematica

Table[PadRight[{},n,n+2],{n,20}]//Flatten (* Harvey P. Dale, Sep 04 2019 *)

Python

from math import isqrt
def A133196(n): return 2+(isqrt(8*n)+1)//2 # Chai Wah Wu, Oct 17 2022

Formula

a(n) = A003056(n)+3, a(n) = A003057(n)+1; a(n) = t+3, where t=floor((-1+sqrt(8*n-7))/2). - Boris Putievskiy, May 07 2013