login
A355444
a(n) = 1 if n is of the form p^2 * q where p and q are primes with p < q < p^2, otherwise 0.
3
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
OFFSET
1
FORMULA
a(n) = A353472(n) * A355454(n).
a(n) = A353474(n) - A355443(n).
MATHEMATICA
a[n_] := If[(f = FactorInteger[n])[[;; , 2]] == {2, 1} && f[[1, 1]]^2 > f[[2, 1]], 1, 0]; Array[a, 100] (* Amiram Eldar, Jul 07 2022 *)
PROG
(PARI) A355444(n) = ((numdiv(n) == (3+bigomega(n))) && issquare(divisors(n)[4]));
CROSSREFS
Characteristic function of A355446.
Sequence in context: A277163 A011726 A297041 * A070109 A355454 A107846
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 02 2022
STATUS
approved