A023583 Greatest prime divisor of 2*prime(n)-1.

3, 5, 3, 13, 7, 5, 11, 37, 5, 19, 61, 73, 3, 17, 31, 7, 13, 11, 19, 47, 29, 157, 11, 59, 193, 67, 41, 71, 31, 5, 23, 29, 13, 277, 11, 43, 313, 13, 37, 23, 17, 19, 127, 11, 131, 397, 421, 89, 151, 457, 31, 53, 37, 167, 19, 7, 179, 541, 79, 17, 113, 13, 613, 23, 5

Offset

1,1

Comments

a(n) = 2*prime(n)-1 if n is in A137288. - Robert Israel, May 19 2020

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

a(n) = A006530(A076274(n+1)). - Bernard Schott, May 20 2020

Maple

f:= n -> max(numtheory:-factorset(2*ithprime(n)-1)):
map(f, [$1..100]); # Robert Israel, May 19 2020

Crossrefs

Cf. A006530, A076274, A137288.

Sequence in context: A023585 A089948 A336806 * A266603 A121278 A023587

Adjacent sequences: A023580 A023581 A023582 * A023584 A023585 A023586

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Robert Israel, May 19 2020

Status

approved