A106126 Numbers k such that k-th semiprime == 1 (mod k).

1, 27, 28, 35, 40, 44, 47, 55, 56, 72, 613400, 613401, 613457, 613482, 613530, 613538, 613544, 613550, 613554, 613556, 613560, 613614, 58155520, 58155521, 58155533, 58155537, 58155540, 58155543, 58155545, 58155571, 6384425460, 6384425506, 6384425524

Offset

1,2

Comments

a(45) > 10^12. - Lucas A. Brown, Oct 17 2020

Links

Lucas A. Brown, Table of n, a(n) for n = 1..44

Lucas A. Brown, semiprimemods.py

Example

27 is a term because the 27th semiprime (i.e., 82) == 1 (mod 27).

Crossrefs

Cf. A001358, A357781.

Sequence in context: A258267 A332927 A031171 * A069551 A022397 A042470

Adjacent sequences: A106123 A106124 A106125 * A106127 A106128 A106129

Keyword

hard,nonn

Author

Shyam Sunder Gupta, May 07 2005

Extensions

a(23)-a(30) from Donovan Johnson, Oct 29 2008

a(1) and a(31)-a(33) from Lucas A. Brown, Oct 17 2020

Status

approved