A284890 a(1)=2, and then a(n+1) = a(n) + k where prime(k) is the least prime dividing a(n).

2, 3, 5, 8, 9, 11, 16, 17, 24, 25, 28, 29, 39, 41, 54, 55, 58, 59, 76, 77, 81, 83, 106, 107, 135, 137, 170, 171, 173, 213, 215, 218, 219, 221, 227, 276, 277, 336, 337, 405, 407, 412, 413, 417, 419, 500, 501, 503, 599, 708, 709, 836, 837, 839, 985, 988, 989

Offset

1,1

Links

Rémy Sigrist, Table of n, a(n) for n = 1..2297

Rémy Sigrist, C program for A284890

Formula

a(n+1) = a(n) + A055396(a(n)) for any n>1.

Example

a(9) = 24 = prime(1)^3*prime(2), hence a(10) = 24+1 = 25.
a(14) = 41 = prime(13), hence a(15) = 41+13 = 54.

Mathematica

NestList[#+PrimePi[FactorInteger[#][[1, 1]]]&, 2, 60] (* Harvey P. Dale, May 08 2022 *)

Crossrefs

Cf. A055396, A076271.

Sequence in context: A285253 A047254 A226815 * A051214 A256722 A364926

Adjacent sequences: A284887 A284888 A284889 * A284891 A284892 A284893

Keyword

nonn

Author

Rémy Sigrist, Apr 05 2017

Status

approved