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A364141
Products k of 4 distinct primes (or tetraprimes) such that k has no squarefree neighbors.
1
3774, 5565, 6726, 8151, 10659, 10934, 11726, 11935, 12426, 13035, 13195, 13674, 13755, 14763, 15042, 15249, 15351, 15785, 16215, 16226, 17630, 17765, 17974, 17985, 18249, 18278, 18915, 18998, 19565, 20085, 21385, 21574, 21855, 22015, 23023, 23345, 23374, 23426, 24038, 24605, 25185
OFFSET
1,1
EXAMPLE
3773 = 7^3 * 11, 3774 = 2 * 3 * 17 * 37, 3775 = 5^2 * 151, so 3774 is a term.
5564 = 2^2 * 13 * 107, 5565 = 3 * 5 * 7 * 53, 5566 = 2 * 11^2 * 23, so 5565 is a term.
MATHEMATICA
Select[Range[26000], FactorInteger[#][[;; , 2]] == {1, 1, 1, 1} && ! SquareFreeQ[# - 1] && ! SquareFreeQ[# + 1] &] (* Amiram Eldar, Jul 10 2023 *)
CROSSREFS
Sequence in context: A108179 A336584 A367791 * A364766 A080953 A178193
KEYWORD
nonn
AUTHOR
Massimo Kofler, Jul 10 2023
STATUS
approved