A135668 a(n) = ceiling(n + sqrt(n)).

2, 4, 5, 6, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67

Offset: 1

Author

Mohammad K. Azarian, Nov 25 2007

Keywords

• nonn
• easy

Comments

Complement of A002061. - Kieren MacMillan, Dec 16 2007

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A134914, A135660, A135661, A135662, A135663, A135664, A135665, A028391, A002061.

Programs

Magma

[Ceiling(n + n^(1/2)): n in [1..100]]; // Vincenzo Librandi, Feb 16 2013

Mathematica

Table[Ceiling[n + n^(1/2)], {n, 100}] (* Vincenzo Librandi, Feb 16 2013 *)

Python

from sympy import integer_nthroot
def A135668(n): return n+(a:=integer_nthroot(n,2))[0]+(not a[1]) # Chai Wah Wu, Aug 26 2024