A301707 a(n) = n * Sum_{k prime<=n} k.

0, 4, 15, 20, 50, 60, 119, 136, 153, 170, 308, 336, 533, 574, 615, 656, 986, 1044, 1463, 1540, 1617, 1694, 2300, 2400, 2500, 2600, 2700, 2800, 3741, 3870, 4960, 5120, 5280, 5440, 5600, 5760, 7289, 7486, 7683, 7880, 9758, 9996, 12083, 12364, 12645, 12926, 15416, 15744

Offset: 1

Author

Pedro Caceres, Mar 25 2018

Keywords

• nonn

Examples

			a(6) = 6 * Sum_{k primes<=6} = 6 * (2+3+5) = 6 * 10 = 60.
		

Crossrefs

Cf. A034387.

Programs

Mathematica

Array[# Sum[Prime@ i, {i, PrimePi@ #}] &, 48] (* Michael De Vlieger, Apr 10 2018 *)

PARI

a(n) = n*sum(k=1, n, k*isprime(k)); \\ Michel Marcus, Mar 26 2018

Formula

a(n) = n * A034387(n).

Extensions

More terms from Michel Marcus, Apr 09 2018