A106129 Numbers k such that the k-th semiprime == 4 (mod k).

1, 2, 5, 37, 38, 58, 61, 70, 77, 613379, 613413, 613415, 613429, 613485, 613509, 613518, 613521, 613533, 613543, 613599, 6384425449, 6384425459, 6384425463, 6384425517, 6384425557, 6384425574, 6384425634

Offset: 1

Author

Shyam Sunder Gupta, May 07 2005

Keywords

• hard
• more
• nonn

Comments

a(28) > 10^12. - Lucas A. Brown, Oct 18 2020

a(28) <= 121769718289846, a(29) <= 121769718289883 and a(38) <= 121769718292241. - Martin Ehrenstein, Oct 28 2022

Examples

			a(3) = 5 is a term because the 5th semiprime is 14 and 14 == 4 (mod 5).
		

Links

• Lucas A. Brown, semiprimemods.py

Crossrefs

Cf. A001358, A357808.

Extensions

a(21)-a(27) by Lucas A. Brown, Oct 18 2020

a(1), a(2) by Lucas A. Brown, Oct 19 2020