A326141 Odd numbers n for which A318879(n) is not zero and A318879(n) divides A318878(n); odd numbers such that A326140(n) = A318879(n).

105, 195, 4785, 22515, 56865, 228285, 237315, 484245, 671853, 1838145, 1946955, 3446895, 4522695, 12955245, 37730865, 52475055, 53568885, 87612975

Offset

1,1

Comments

Not a subsequence of A036798, even though many terms are members.

Questions: Are all terms multiples of three? Multiples of 3^(2k+1) but not of 3^(2k)? Are any of the terms included in A228058, A326137?

Links

Table of n, a(n) for n=1..18.

Index entries for sequences where any odd perfect numbers must occur

Prog

(PARI) isA326141(n) = if(!(n%2), 0, my(t=0, u=0); fordiv(n, d, d -= 2*eulerphi(d); if(d<0, t -= d, u += d)); (gcd(t, u)==u));

Crossrefs

Cf. A033879, A083254, A036798, A228058, A318878, A318879, A326137, A326140.

Cf. also A325981, A326131.

Sequence in context: A046887 A026066 A167629 * A347881 A044337 A044718

Adjacent sequences: A326138 A326139 A326140 * A326142 A326143 A326144

Keyword

nonn,more

Author

Antti Karttunen, Jun 09 2019

Status

approved