A193322 Sum of even divisors of lambda(n).

0, 0, 2, 2, 6, 2, 8, 2, 8, 6, 12, 2, 24, 8, 6, 6, 30, 8, 26, 6, 8, 12, 24, 2, 36, 24, 26, 8, 48, 6, 48, 14, 12, 30, 24, 8, 78, 26, 24, 6, 84, 8, 64, 12, 24, 24, 48, 6, 64, 36, 30, 24, 84, 26, 36, 8, 26, 48, 60, 6, 144, 48, 8, 30, 24, 12, 96, 30, 24, 24, 96, 8, 182, 78, 36, 26, 48, 24, 112, 6, 80, 84, 84, 8, 30, 64

Offset

1,3

Comments

Lambda is the function in A002322.

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Formula

a(n) = A146076(A002322(n)). - Michel Marcus, Mar 18 2016

Example

a(17) = 30 because lambda(17) = 16 and the sum of the 4 even divisors { 2, 4, 8, 16} is 30.

Mathematica

Table[Total[Select[Divisors[CarmichaelLambda[n]], EvenQ[ # ]&]], {n, 62}]
(* Second program: *)
Array[DivisorSum[CarmichaelLambda@ #, # &, EvenQ] &, 86] (* Michael De Vlieger, Dec 04 2017 *)

Prog

(PARI) a(n) = sumdiv(lcm(znstar(n)[2]), d, d*(1-(d%2))); \\ Michel Marcus, Mar 18 2016

Crossrefs

Cf. A002322, A146076, A191613.

Sequence in context: A167556 A221438 A327991 * A165460 A242649 A294876

Adjacent sequences: A193319 A193320 A193321 * A193323 A193324 A193325

Keyword

nonn

Author

Michel Lagneau, Jul 22 2011

Extensions

More terms from Antti Karttunen, Dec 04 2017

Status

approved