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 A023583 Greatest prime divisor of 2*prime(n)-1. 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 (list; graph; refs; listen; history; text; internal format)
 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

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Last modified June 5 12:07 EDT 2023. Contains 363136 sequences. (Running on oeis4.)