A349793 - OEIS

A349793

Primes which are the nearest integer to the harmonic mean of the previous prime and the following prime.

3, 7, 13, 23, 47, 89, 157, 173, 257, 263, 373, 563, 593, 607, 653, 733, 947, 977, 1103, 1123, 1187, 1223, 1367, 1511, 1747, 1753, 1907, 2287, 2417, 2677, 2903, 2963, 3307, 3313, 3637, 3733, 4013, 4409, 4457, 4597, 4657, 4691, 4993, 5107, 5113, 5303, 5387, 5393

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

PROG

(PARI) a349793(limit) = {my(p1=2, p2=3); forprime(p3=5, limit, my(hm=round((2*p1*p3)/(p1+p3))); if(p2==hm, print1(p2, ", ")); p1=p2; p2=p3)};

a349793(5500)

CROSSREFS

Cf. A006562, A046869, A051635, A075540, A216124.

Sequence in context: A048462 A048465 A049112 * A100720 A297852 A297953

Adjacent sequences: A349790 A349791 A349792 * A349794 A349795 A349796

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Nov 30 2021

STATUS

approved