OFFSET
1,1
COMMENTS
The number of terms <= 10^n: 0, 3, 28, 311, 3541, for n = 1, 2, 3, 4, 5.
Sequence A353011 lists the indices n such that A090395(k) > A090395(n) for all k > n. This allows one to know whether a given number is in this sequence or not. - M. F. Hasler, Apr 15 2022
Another way to confirm a 0 is by looking at A005179(m)/m. If A005179(m)/m > n then d(k) cannot be a multiple of m. - David A. Corneth, Apr 16 2022
LINKS
M. F. Hasler and David A. Corneth, Table of n, a(n) for n = 1..10000 (first 3541 terms from M. F. Hasler)
MATHEMATICA
a = Table[0, {2000}]; Do[m = n; b = Denominator[ DivisorSigma[0, n]/n]; If[b < 2001 && a[[b]] == 0, a[[b]] = n], {n, 1, 25000000}]; Select[ Range[2000], a[[ # ]] == 0 &]
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Feb 09 2004
EXTENSIONS
Edited by M. F. Hasler, Apr 04 2022
STATUS
approved