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A106126
Numbers k such that k-th semiprime == 1 (mod k).
2
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, semiprimemods.py
EXAMPLE
27 is a term because the 27th semiprime (i.e., 82) == 1 (mod 27).
CROSSREFS
Sequence in context: A258267 A332927 A031171 * A069551 A022397 A042470
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