A093818 a(n) = gcd(A001008(n), n!).

1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 3, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 11, 1, 1, 1, 11, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset: 1

Author

Vladeta Jovovic, May 20 2004

Keywords

• easy
• nonn

Comments

Conjecture: every odd prime occurs as a term in the sequence.

Observation: Terms other than 1 are rare. Of the terms a(1) .. a(29524), only 187 are larger than one. Among these 187 terms, the following 50 distinct values occur: 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 227, 257, 269, 509, 863, 919, 1049, 1331, 9409, 11881. Of these, all other are primes except 121 = 11*11, 1331 = 11*11*11, 9409 = 97*97 and 11881 = 109*109. - Antti Karttunen, Aug 28 2017

Links

• Antti Karttunen, Table of n, a(n) for n = 1..29524

Crossrefs

Cf. A001008, A060746.

Programs

PARI

A001008(n) = numerator(sum(i=1, n, 1/i)); \\ This function from Michael B. Porter, Dec 08 2009
A093818(n) = gcd(A001008(n),n!); \\ Antti Karttunen, Aug 28 2017

Extensions

More terms from David Wasserman, Apr 20 2007

Name edited (A001008 substituted for "Wolstenholme") by Antti Karttunen, Aug 28 2017