A145097 a(n) is the largest proper divisor of the Mersenne composite A065341(n).

89, 178481, 2304167, 616318177, 164511353, 20408568497, 59862819377, 1416003655831, 3203431780337, 761838257287, 10334355636337793, 21514198099633918969, 224958284260258499201, 57912614113275649087721

Offset

1,1

Comments

Note that not all the largest divisors are primes.

Which divisors are prime? - see A145099. - Artur Jasinski, Oct 04 2008

Links

Amiram Eldar, Table of n, a(n) for n = 1..183

Mathematica

a = {}; Do[m = 2^Prime[n] - 1; If[PrimeQ[m], null, AppendTo[a, Divisors[m][[ -2]]]], {n, 1, 40}]; a

Crossrefs

Cf. A065341, A135975, A135980, A136031.

Sequence in context: A089158 A145098 A136031 * A287054 A080051 A243316

Adjacent sequences: A145094 A145095 A145096 * A145098 A145099 A145100

Keyword

nonn

Author

Artur Jasinski, Oct 01 2008

Extensions

Name clarified by Amiram Eldar, Mar 12 2020

Status

approved