A309222 a(0) = 6; thereafter a(n) = a(n-1) + prime(n) if prime(n) > a(n-1), otherwise a(n) = a(n-1) - prime(n).

6, 4, 1, 6, 13, 2, 15, 32, 13, 36, 7, 38, 1, 42, 85, 38, 91, 32, 93, 26, 97, 24, 103, 20, 109, 12, 113, 10, 117, 8, 121, 248, 117, 254, 115, 264, 113, 270, 107, 274, 101, 280, 99, 290, 97, 294, 95, 306, 83, 310, 81, 314, 75, 316, 65, 322, 59, 328, 57, 334, 53, 336, 43, 350, 39, 352

Offset: 0

Author

N. J. A. Sloane, Aug 29 2019

Keywords

• nonn
• look

Comments

Hugo van der Sanden asks if this ever reaches 0. He finds that a(n) > 0 for n < 5*10^10. Probabilistic arguments suggest it will never reach 0.

References

• Hugo van der Sanden, Posting to Sequence Fans Mailing List, Aug 28 2019

Links

• N. J. A. Sloane, Table of n, a(n) for n = 0..20000

Crossrefs

If we start with 0 or 1 instead of 6 we get A008348, A022837.

Similar in spirit to A008344, and has a similar graph.