A035254 First differences of A035253.

-3, -1, 1, 2, 4, 5, 6, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 64

Offset: 0

Author

Robet Bronson (bob(AT)bronsons.com)

Keywords

• sign
• easy

Crossrefs

Different from A030124. Cf. A002024, A014132, A014133. First differences are in A035214.

Programs

Python

from math import isqrt
def A035254(n): return n+(isqrt(n<<3)-5>>1) # Chai Wah Wu, Jun 07 2025

Formula

a(n) = A002024(n)+n-3. - Chai Wah Wu, Jun 07 2025