login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A106126 Numbers k such that k-th semiprime == 1 (mod k). 1
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 (list; graph; refs; listen; history; text; internal format)
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

EXAMPLE

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

CROSSREFS

Cf. A001358.

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 20 10:21 EDT 2021. Contains 348100 sequences. (Running on oeis4.)