A112817 Numbers k such that lcm(1,2,3,...,k)/11 equals the denominator of the k-th harmonic number H(k).

33, 34, 35, 36, 37, 38, 39, 40, 41, 81, 82, 83, 84, 85, 86, 87, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430

Offset: 1

Author

Robert G. Wilson v, Sep 17 2005

Keywords

• nonn

Comments

When 11 occurs in A110566.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Jinyuan Wang)

Crossrefs

Cf. A002805, A003418, A110566.

Cf. A098464, A112813, A112814, A112815, A112816, A112818, A112819, A112820, A112821, A112822.

Programs

Mathematica

f[n_] := LCM @@ Range[n]/Denominator[ HarmonicNumber[n]]; Select[ Range[430], f[ # ] == 11 &]
Select[Range[450],1/11*LCM@@Range[#]==Denominator[HarmonicNumber[#]]&] (* Harvey P. Dale, Jan 06 2019 *)

Extensions

Name (definition) corrected by Harvey P. Dale, Jan 06 2019