OFFSET
1,1
COMMENTS
The least odd term is a(90) = 11025, and the least term that is coprime to 6 is 1382511906801025.
Are there two consecutive integers in this sequence? There are none below 10^22.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10534 (terms not exceeding 10^8)
EXAMPLE
36 = 2^2 * 3^2 is a term since it is powerful, and sigma(36) = 91 > 2*36 = 72.
MATHEMATICA
Select[Range[4000], DivisorSigma[-1, #] > 2 && Min[FactorInteger[#][[;; , 2]]] > 1 &]
PROG
(PARI) is(n) = { my(f = factor(n)); n > 1 && vecmin(f[, 2]) > 1 && sigma(f, -1) > 2; }
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, May 19 2023
STATUS
approved