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A268112 Numbers n such that at least one prime p exists such that p < n and v_p(H_n) >= 3, where v_p(x) is the p-adic valuation of x and H_i is the i-th Harmonic number. 0
848, 9338, 10583, 3546471722268916272 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The corresponding p for 848, 9338 and 10583 is 11.

LINKS

Table of n, a(n) for n=1..4.

C. Krattenthaler and T. Rivoal, On the integrality of the Taylor coefficients of mirror maps, II, Communications in Number Theory and Physics, Volume 3, Number 3 (2009), 555-591.

PROG

(PARI) is(n) = forprime(p=1, n-1, if(valuation((numerator(sum(i=1, n, 1/i))), p) > 2, return(1))); return(0)

CROSSREFS

Cf. A001008.

Sequence in context: A252253 A247532 A235065 * A194618 A252546 A251257

Adjacent sequences:  A268109 A268110 A268111 * A268113 A268114 A268115

KEYWORD

nonn,hard,more

AUTHOR

Felix Fröhlich, Jan 26 2016

STATUS

approved

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Last modified March 19 04:23 EDT 2019. Contains 321311 sequences. (Running on oeis4.)