A106132 Numbers k such that the k-th semiprime == 7 (mod k).

1, 7, 9, 66, 6675, 6918, 613374, 613412, 613418, 613422, 613428, 613434, 613510, 613512, 613514, 613520, 613542, 58155531, 58155569, 58155572, 6384425518, 6384425556, 819217006165, 819217006175, 819217006199, 819217006203, 819217006227, 819217006665, 819217006869

Offset

1,2

Comments

a(30) > 10^12. - Lucas A. Brown, Oct 18 2020

Links

Table of n, a(n) for n=1..29.

Lucas A. Brown, semiprimemods.py

Example

a(3)=9 is a term because the 9th semiprime (i.e., 25) == 7 (mod 9).

Crossrefs

Cf. A001358, A356357.

Sequence in context: A263836 A087336 A178427 * A285011 A317401 A137058

Adjacent sequences: A106129 A106130 A106131 * A106133 A106134 A106135

Keyword

hard,nonn

Author

Shyam Sunder Gupta, May 07 2005

Extensions

a(18)-a(20) from Donovan Johnson, Oct 29 2008

a(21)-a(29) by Lucas A. Brown, Oct 18 2020

a(1), a(2) by Lucas A. Brown, Nov 22 2020

Status

approved