A228423 Sum of the squared primes less than or equal to n.

0, 0, 0, 4, 4, 4, 4, 4, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 38, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87, 87

Offset: 1

Author

Wesley Ivan Hurt, Nov 09 2013

Keywords

• nonn

Examples

			a(10) = 13; 4 and 9 are the only squared primes less than or equal to 10 and their sum is 13.
		

Crossrefs

Cf. A024450.

Cf. A081738, A000196.

Programs

Maple

with(numtheory); a:=n->add('if'(bigomega(i)=2, i*(1-mobius(i)), 0), i=1..n); seq(a(n), n=1..100);

Mathematica

With[{sp=Prime[Range[10]]^2},Table[Total[Select[sp,#<=n&]],{n,100}]] (* Harvey P. Dale, Nov 11 2016 *)

Formula

a(n) = Sum_{ i <= n | Omega(i) = 2} i * (1 - mu(i)).

a(n) = A081738(A000196(n)). - Michel Marcus, Aug 20 2023