A183224 Complement of the 12-gonal numbers.

2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101

Offset: 1

Author

Clark Kimberling, Jan 01 2011

Keywords

• nonn

Crossrefs

Cf. A051624 (12-gonal numbers.)

Programs

Mathematica

Table[n+Floor[1/2+(n/5+1/5)^(1/2)], {n,100}]

Python

from math import isqrt
def A183224(n): return n+(isqrt((n<<2|2)//5)+1>>1) # Chai Wah Wu, Oct 06 2024

Formula

a(n) = n + floor(1/2+(n/5+1/5)^(1/2)).