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A112814 Numbers k such that lcm(1,2,3,...,k)/5 equals the denominator of the k-th harmonic number H(k). 12
105, 106, 107, 108, 109, 2625, 2626, 2627, 2628, 2629, 2630, 2631, 2632, 2633, 2634, 2635, 2636, 2637, 2638, 2639, 2640, 2641, 2642, 2643, 2644, 2645, 2646, 2647, 2648, 2649, 2650, 2651, 2652, 2653, 2654, 2655, 2656, 2657, 2658, 2659, 2660, 2661, 2662 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

When 5 occurs in A110566.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

f[n_] := LCM @@ Range[n]/Denominator[ HarmonicNumber[n]]; Select[ Range[2662], f[ # ] == 5 &]

PROG

(PARI) isok(n) = lcm(vector(n, i, i)) == 5*denominator(sum(i=1, n, 1/i)); \\ Michel Marcus, Mar 07 2018

CROSSREFS

Cf. A002805, A003418, A110566.

Cf. A098464, A112813, A112815, A112816, A112817, A112818, A112819, A112820, A112821, A112822.

Sequence in context: A069172 A231578 A104437 * A058179 A260461 A090055

Adjacent sequences:  A112811 A112812 A112813 * A112815 A112816 A112817

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Sep 17 2005

STATUS

approved

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Last modified September 17 03:42 EDT 2021. Contains 347478 sequences. (Running on oeis4.)