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

1,7

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

Prog

(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

Crossrefs

Cf. A001008, A060746.

Sequence in context: A370079 A318497 A202150 * A097031 A354997 A327537

Adjacent sequences: A093815 A093816 A093817 * A093819 A093820 A093821

Keyword

easy,nonn

Author

Vladeta Jovovic, May 20 2004

Extensions

More terms from David Wasserman, Apr 20 2007

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

Status

approved