A127925 Primes p such that 2p < prime(k-i) + prime(k+i) for i=1..k-1, where p=prime(k).

3, 7, 19, 23, 43, 47, 73, 109, 113, 199, 283, 293, 313, 317, 463, 467, 503, 509, 523, 619, 661, 683, 691, 887, 1063, 1069, 1109, 1129, 1303, 1307, 1321, 1327, 1613, 1621, 1627, 1637, 1669, 1789, 2143, 2161, 2383, 2393, 2399, 2477, 2731, 2753, 2803, 2861, 2971

Offset: 1

Author

T. D. Noe, Feb 06 2007

Keywords

• nonn

Comments

One of several sets of "good primes" in section A14 of Guy.

McNew calls these numbers "midpoint convex primes". - Peter Munn, Jul 04 2025

References

• R. K. Guy, Unsolved Problems in Number Theory, 3rd ed. Springer, 2004.

Links

• T. D. Noe, Table of n, a(n) for n=1..10001
• Nathan McNew, Popular values of the largest prime divisor function (corrected version), page 16, November 2015.

Crossrefs

Cf. A028388.

A246033 is a subset.

Subset of A124661, A178954.

Programs

Mathematica

t={}; n=1; While[Length[t]<100, n++; p=Prime[n]; i=1; While[i