A136365 Numbers k such that A075986(k) is prime.

1, 171, 210, 550, 1445, 1809, 2176, 2719

Offset

1,2

Links

Table of n, a(n) for n=1..8.

Mathematica

f=1; Do[ p=Prime[n]; f=f + 1/p^2; g=Numerator[ f ]; If[ PrimeQ[ g ], Print[ {n, g} ] ], {n, 1, 210} ]

Crossrefs

Cf. A075986 (numerator of 1 + 1/p(1)^2 + ... + 1/p(n)^2, where p(k) = prime(k)).

Cf. A024528, A125707.

Cf. A136366, A136367, A136368, A136369, A136370, A136371.

Sequence in context: A045149 A031511 A101273 * A031900 A349097 A120819

Adjacent sequences: A136362 A136363 A136364 * A136366 A136367 A136368

Keyword

nonn,hard,more

Author

Alexander Adamchuk, Dec 27 2007

Extensions

a(4)-a(8) from Robert Price, Aug 26 2019

Status

approved