A321995 Indices of highly composite numbers A002182 which are between a twin prime pair.

3, 4, 5, 9, 11, 12, 20, 28, 30, 84, 108, 118, 143, 149, 208, 330, 362, 1002, 2395, 3160, 10535

Offset: 1

Author

M. F. Hasler, Jun 23 2019

Keywords

• nonn
• more

Comments

The highly composite numbers are listed in A068507, but their growth is such that one cannot list the terms beyond A002182(362), corresponding to a(17), in the DATA section.

The term a(21) corresponds to A002182(10535) = A108951(52900585920). - Daniel Suteu, Jun 27 2019

a(22) > 779674, if it exists. - Amiram Eldar, Dec 03 2020

Crossrefs

Cf. A068507, A002182, A002822.

Programs

PARI

select( x->ispseudoprime(x-1)&&ispseudoprime(x+1), A2182, 1) \\ assuming A2182 holds enough terms of A002182. - M. F. Hasler, Jun 23 2019

Formula

Intersection of A306587 and A306588. - Daniel Suteu, Jun 27 2019

Extensions

a(21) from Daniel Suteu, Jun 27 2019 (obtained from A. Flammenkamp's data)