A267087 a(n) = ceiling(A007504(n)/n) + floor(A007504(n)/n).

4, 5, 7, 9, 11, 13, 17, 19, 23, 25, 29, 33, 37, 41, 43, 47, 51, 55, 59, 63, 67, 71, 76, 81, 85, 89, 93, 97, 103, 107, 111, 115, 121, 125, 131, 135, 139, 145, 149, 155, 159, 165, 169, 175, 179, 183, 189, 195, 199, 205, 209, 215, 220, 225, 231, 235, 241

Offset

1,1

Comments

Primes not in this sequence 2, 3, 31, 53, 61, 73, 79, 83, 101, 109, 113, 127, 137, 151,...

a(n) is even for n=1, 23, 53, 853, ... see A045345.

It appears that there are infinitely many even terms in this sequence but that they have density zero.

References

Javier Cilleruelo and Florian Luca, On the sum of the first n primes, Q. J. Math. 59:4 (2008), 14 pp.

Links

Table of n, a(n) for n=1..57.

Mathematica

Table[Ceiling[(Plus@@Prime[Range[n]])/n]+Floor[(Plus@@Prime[Range[n]])/n], {n, 100}]

Crossrefs

Cf. A007504, A045345, A060620, A158682, A225804, A267084.

Sequence in context: A032492 A223134 A339690 * A050560 A204664 A349482

Adjacent sequences: A267084 A267085 A267086 * A267088 A267089 A267090

Keyword

nonn,easy

Author

Ctibor O. Zizka, Jan 10 2016

Status

approved