A351649 a(n) = minimal average of a pair of twin primes m, such that m * twin_prime(n) is the average of another pair of twin primes, or -1 if no m exists.

4, 6, 6, 18, 150, 6, 12, 12, 42, 30, 30, 18, 462, 18, 570, 42, 6, 6, 102, 6, 12, 12, 420, 192, 18, 600, 5100, 570, 18, 4050, 30, 42, 18, 60, 12, 12, 6, 102, 6, 6, 108, 42, 42, 18, 570, 30, 180, 108, 2970, 12, 60, 270, 12, 60, 42, 60, 1950, 102, 108, 18, 72, 348

Offset

1,1

Links

Table of n, a(n) for n=1..62.

Carlos Rivera, Puzzle 1075: A conjecture about twin primes, The Prime Puzzles and Problems Connection.

Example

11 is the fourth twin prime, i.e., A001097(4). 18 is the minimal average of a twin prime pair, i.e., (17,19), where 18*11=198 is the average of the twin prime pair (197,199). So, a(4)=18.

Crossrefs

Cf. A001097, A014574.

Sequence in context: A346675 A077038 A053320 * A019090 A145692 A295512

Adjacent sequences: A351646 A351647 A351648 * A351650 A351651 A351652

Keyword

nonn

Author

Ivan N. Ianakiev, Feb 16 2022

Extensions

More terms from Jinyuan Wang, Feb 16 2022

Status

approved