A051616 - OEIS

A051616

Primes p for which A051614(p) is 3 but are not Sophie Germain primes.

17, 47, 71, 107, 137, 167, 197, 227, 257, 263, 317, 347, 401, 449, 467, 557, 569, 587, 599, 617, 647, 677, 701, 797, 827, 839, 857, 863, 881, 887, 929, 947, 971, 977, 1061, 1097, 1181, 1187, 1217, 1259, 1277, 1283, 1307, 1367, 1373, 1427, 1433, 1487, 1493

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..49.

FORMULA

p values so that F(2*p*F(2*p+1)+1)=3 and 2p+1 is not prime; F(x) is the least prime divisor of x.

CROSSREFS

Cf. A000945, A051309-A051335, A005384 (Sophie Germain primes).

Sequence in context: A034783 A275770 A126912 * A061275 A128468 A031374

Adjacent sequences: A051613 A051614 A051615 * A051617 A051618 A051619

KEYWORD

nonn

AUTHOR

Labos Elemer

EXTENSIONS

Name corrected by Sean A. Irvine, Sep 22 2021

STATUS

approved