A348788 Values of A347113(k) for k in A348787.

1, 12, 15, 18, 24, 30, 27, 32, 36, 40, 42, 44, 48, 56, 50, 54, 60, 63, 66, 64, 70, 65, 68, 72, 69, 75, 78, 76, 84, 80, 87, 77, 81, 88, 91, 90, 98, 93, 92, 96, 100, 105, 102, 99, 104, 108, 110, 114, 120, 132, 112, 115, 124, 130, 119, 123, 126, 125, 128, 135, 138, 129, 136, 140, 144, 150, 141, 147, 152, 156, 148, 153, 160, 154, 162, 155

Offset: 1

Author

N. J. A. Sloane, Nov 20 2021

Keywords

• nonn

Comments

By definition, the points (A348787(k), a(k)) form the main diagonal of A347113.

It appears that apart from a very small number of exceptions this sequence consists of the numbers that are neither primes nor twice primes (A264828).

The known exceptions (based on the first 20000 terms) are: (a) the three primes A347113(1423) = 1327, A347113(10686) = 9967, and A347113(83051) = 77647 that are unusually close to the line y=x, and (b) the 27 terms [8, 9, 16, 20, 21, 25, 28, 33, 35, 39, 45, 49, 51, 52, 55, 57, 85, 95, 111, 116, 117, 121, 133, 143, 145, 169, 187] which are in A264828 but are not in the present sequence.

This list of 27 exceptions is surprisingly similar to A181780, but this may be just a coincidence.

Links

• N. J. A. Sloane, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A264828, A347113, A348787, A181780.