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A060015 Sum of orders of all even permutations of n letters. 5
1, 1, 7, 31, 211, 1411, 12601, 137047, 1516831, 18111751, 223179001, 2973194071, 46287964867, 835826439631, 15722804528341, 292673102609791, 5177400032329231, 102538737981192607, 2284570602107946601 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

Joshua Harrington, Lenny Jones, and Alicia Lamarche, Characterizing Finite Groups Using the Sum of the Orders of the Elements, International Journal of Combinatorics, Volume 2014, Article ID 835125, 8 pages; http://dx.doi.org/10.1155/2014/835125

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

For n = 4 there is 1 even permutation (1) of order 1, 3 even permutations (12)(34) etc. of order 2 and 8 (123) etc. of order 3, for a total of 31.

MATHEMATICA

g[list_]:=Total[list]!/Apply[Times, list]/Apply[Times, Table[Count[list, n]!, {n, 1, 20}]]; f[list_]:=Apply[Plus, Table[Count[list, n], {n, 2, 20, 2}]]; Map[Total, Table[Map[g, Select[Partitions[n], EvenQ[f[#]]&]]*Map[Apply[LCM, #]&, Select[Partitions[n], EvenQ[f[#]]&]], {n, 1, 20}]]  (* Geoffrey Critzer, Mar 26 2013 *)

CROSSREFS

Cf. A060014.

Sequence in context: A223144 A155521 A201116 * A261558 A241456 A094711

Adjacent sequences:  A060012 A060013 A060014 * A060016 A060017 A060018

KEYWORD

nonn,nice,easy

AUTHOR

N. J. A. Sloane, Mar 17 2001

EXTENSIONS

More terms from Vladeta Jovovic, Mar 18 2001

STATUS

approved

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Last modified October 16 13:51 EDT 2019. Contains 328093 sequences. (Running on oeis4.)