A140198 A002326((k-1)/2) for composite numbers k from A141229.

18, 100, 1210, 2028, 6498, 23548, 49284, 146068, 201898, 223260, 296274, 564898, 1020100, 1213594, 2230930, 2666298, 3285748, 4304178, 5147788, 5703298, 5896980, 7606564, 9349410, 11645554, 19392748, 25067908, 31754524, 41661514, 42386748, 51755988, 54296298

Offset

1,1

Links

Table of n, a(n) for n=1..31.

Mathematica

r[n_] := EulerPhi[n]/MultiplicativeOrder[2, n]; d[n_] := DivisorSum[n, r[#] &]; f[n_] := (m = MultiplicativeOrder[2, n])*d[n] - m + 1; MultiplicativeOrder[2, #] & /@  Select[Range[10^5], CompositeQ[#] && Total@(r /@ Divisors[#]) - 1 == 3 &] (* Amiram Eldar, Sep 12 2019 *)

Crossrefs

Cf. A002326, A141229, A001122, A006694.

Sequence in context: A359435 A301542 A231138 * A107600 A229326 A365107

Adjacent sequences: A140195 A140196 A140197 * A140199 A140200 A140201

Keyword

nonn

Author

Vladimir Shevelev, Jun 15 2008

Extensions

a(4) corrected and more terms added by Amiram Eldar, Sep 12 2019

Status

approved