

A092193


Number of generations for which prime(n) divides A001008(k) for some k.


4



4, 3, 7, 30, 3, 3, 7, 3, 5, 7, 4, 3, 5, 5, 6, 6, 4, 3, 8, 3, 3
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OFFSET

2,1


COMMENTS

For any prime p, generation m consists of the numbers p^(m1) <= k < p^m. The zeroth generation consists of just the number 0. When there is a k in generation m such that p divides A001008(k), then that k may generate solutions in generation m+1. It is conjectured that for all primes there are solutions for only a finite number of generations. The number of generations is unknown for p=83.
Boyd's table 3 states incorrectly that harmonic primes have 2 generations; harmonic primes have 3 generations.


LINKS

Table of n, a(n) for n=2..22.
David W. Boyd, A padic study of the partial sums of the harmonic series, Experimental Math., Vol. 3 (1994), No. 4, 287302.
A. Eswarathasan and E. Levine, pintegral harmonic sums, Discrete Math. 91 (1991), 249257.


EXAMPLE

a(4)=7 because the fourth prime, 7, divides A001008(k) for k = 6, 42, 48, 295, 299, 337, 341, 2096, 2390, 14675, 16731, 16735 and 102728. These values of k fall into 6 generations; adding the zeroth generation makes a total of 7 generations.


CROSSREFS

Cf. A072984 (least k such that prime(n) divides A001008(k)), A092101 (harmonic primes), A092102 (nonharmonic primes).
Sequence in context: A048227 A213661 A176083 * A277117 A155910 A199077
Adjacent sequences: A092190 A092191 A092192 * A092194 A092195 A092196


KEYWORD

more,nonn


AUTHOR

T. D. Noe, Feb 24 2004; corrected Jul 28 2004


STATUS

approved



