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

1,1

Links

Table of n, a(n) for n=1..97.

Formula

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

Mathematica

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

Prog

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

Crossrefs

Cf. A051624 (12-gonal numbers.)

Sequence in context: A302839 A130572 A353838 * A357862 A383397 A098240

Adjacent sequences: A183221 A183222 A183223 * A183225 A183226 A183227

Keyword

nonn

Author

Clark Kimberling, Jan 01 2011

Status

approved