A351875 Positive difference of the distinct prime factors of A129521(n).

1, 2, 6, 18, 30, 36, 78, 96, 138, 156, 198, 210, 228, 270, 306, 330, 336, 366, 378, 438, 498, 546, 576, 600, 606, 618, 660, 690, 726, 810, 828, 876, 936, 966, 996, 1008, 1068, 1170, 1236, 1278, 1296, 1398, 1428, 1458, 1530, 1608, 1626, 1656, 1758, 1866, 2010, 2028, 2088, 2130

Offset

1,2

Links

Table of n, a(n) for n=1..54.

Formula

a(n) = A005383(n) - A005382(n).

a(n) = A005382(n) - 1. - Amiram Eldar, Feb 23 2022

Example

a(4) = 18; A005383(4) - A005382(4) = 37 - 19 = 18.

Mathematica

Select[Prime[Range[350]], PrimeQ[2*# - 1] &] - 1 (* Amiram Eldar, Feb 23 2022 *)

Crossrefs

Cf. A005382, A005383, A129521.

Sequence in context: A257065 A066286 A324541 * A197168 A373515 A288815

Adjacent sequences: A351872 A351873 A351874 * A351876 A351877 A351878

Keyword

nonn

Author

Wesley Ivan Hurt, Feb 22 2022

Status

approved