A133440 a(1)=1; a(n) = Sum_{1<=k<=n, gcd(k,n)=1} floor(sqrt(k)).

1, 1, 2, 2, 5, 3, 9, 6, 10, 7, 19, 8, 25, 13, 17, 18, 38, 15, 46, 21, 33, 27, 62, 23, 58, 36, 56, 38, 90, 26, 100, 54, 69, 55, 84, 43, 131, 66, 90, 61, 155, 48, 167, 80, 97, 90, 191, 67, 178, 86, 139, 105, 231, 81, 181, 110, 166, 130, 273, 76, 287, 144, 175, 156, 235, 100

Offset

1,3

Links

Table of n, a(n) for n=1..66.

Example

The positive integers that are < 12 and are coprime to 12 are 1,5,7,11. The floors of the square roots of these are 1,2,2,3. So a(12) = 1+2+2+3 = 8.

Mathematica

Table[Plus @@ (Floor[Sqrt[Select[Range[n], GCD[ #, n] == 1 &]]]), {n, 1, 70}] (* Stefan Steinerberger, Dec 01 2007 *)

Crossrefs

Sequence in context: A006307 A152991 A163298 * A331520 A160793 A327754

Adjacent sequences: A133437 A133438 A133439 * A133441 A133442 A133443

Keyword

nonn

Author

Leroy Quet, Nov 26 2007

Extensions

More terms from Stefan Steinerberger, Dec 01 2007

Status

approved