A061887 n + largest square less than or equal to n; numbers in the range [2k^2,2k^2+2k] for some k.

0, 2, 3, 4, 8, 9, 10, 11, 12, 18, 19, 20, 21, 22, 23, 24, 32, 33, 34, 35, 36, 37, 38, 39, 40, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 128, 129

Offset: 0

Author

Henry Bottomley, May 12 2001

Keywords

• nonn

Examples

			a(15)=15+9=24; a(16)=16+16=32; a(17)=17+16=33.
		

Crossrefs

Cf. A060984, A061885.

Programs

Mathematica

Table[n+Floor[Sqrt[n]]^2,{n,0,70}] (* Harvey P. Dale, Aug 23 2012 *)

Formula

a(n) = n+[sqrt(n)]^2 = n+A048760(n) = 2n-A053186(n).