A366171 Integers k such that (2^(k+3)-2^k-1)/5 is prime.
3, 7, 19, 27, 31, 39, 151, 199, 451, 2371, 2511, 7859, 103819
Offset: 1
Links
- Vedant Aryan, Dev Madhavani, Savan Parikh, Ingrid Slattery, and Joshua Zelinsky, On 2-Near Perfect Numbers, arXiv:2310.01305 [math.NT], 2023. See p. 15.
Crossrefs
Cf. A366172 (strongly 2-near perfect numbers).
Programs
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PARI
isok(k) = my(x=(2^(k+3)-2^k-1)/5); (denominator(x)==1) && ispseudoprime(x);
Extensions
a(13) from Michael S. Branicky, Oct 05 2023
Comments