A211306 Numerator of Sum_{k=1..n} 1/lambda(k), where lambda(k) is the Carmichael's lambda function.

1, 2, 5, 3, 13, 15, 47, 53, 55, 29, 74, 163, 331, 341, 89, 371, 1499, 513, 4657, 4837, 4957, 5029, 55679, 59639, 12007, 12139, 12227, 12491, 87833, 90605, 454873, 461803, 467347, 117703, 59429, 30292, 121553, 122323, 61739, 126943, 254579, 259199, 259859

Offset

1,2

Links

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

Example

1, 2, 5/2, 3, 13/4, 15/4, 47/12, 53/12, 55/12, 29/6, 74/15, 163/30, ...

Maple

with(numtheory): a:=n->numer(sum(1/lambda(k), k=1..n)): seq(a(n), n=1..50);

Mathematica

Numerator[Table[Sum[1/CarmichaelLambda[k], {k, 1, n}], {n, 1, 50}]]
Numerator @ Accumulate @ Table[1 / CarmichaelLambda[n], {n, 1, 50}] (* Amiram Eldar, Sep 19 2019 *)

Crossrefs

Cf. A002322, A028415, A212716 (denominator).

Sequence in context: A091265 A262373 A028415 * A267101 A035334 A243506

Adjacent sequences: A211303 A211304 A211305 * A211307 A211308 A211309

Keyword

nonn,frac

Author

Michel Lagneau, May 25 2012

Status

approved