A061887 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..65.

FORMULA

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

EXAMPLE

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

MATHEMATICA

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

CROSSREFS