A362507 Squarefree semiprimes (products of two distinct primes) between sphenic numbers (products of three distinct primes).

1546, 2066, 2234, 2554, 3334, 3566, 3814, 4586, 4894, 4946, 5422, 5594, 6098, 6602, 6694, 6746, 7286, 7346, 7706, 7846, 7886, 8042, 8114, 8438, 8986, 9094, 9806, 10154, 10294, 10786, 10834, 10886, 11038, 11138, 11246, 11846, 12094, 13406, 13714, 13894, 13982, 14002, 14054

Offset

1,1

Links

Table of n, a(n) for n=1..43.

Example

1546 = 2*773 (between 1545 = 3*5*103 and 1547 = 7*13*17)
2066 = 2*1033 (between 2065 = 5*7*59 and 2067 = 3*13*53)
2234 = 2*1117 (between 2233 = 7*11*29 and 2235 = 3*5*149)

Mathematica

SequencePosition[Table[FactorInteger[n][[;; , 2]], {n, 2, 15000}], {{1, 1, 1}, {1, 1}, {1, 1, 1}}][[;; , 2]] (* Amiram Eldar, Apr 23 2023 *)

Crossrefs

Cf. A006881, A007304.

Sequence in context: A232102 A234031 A038009 * A249008 A249473 A246899

Adjacent sequences: A362504 A362505 A362506 * A362508 A362509 A362510

Keyword

nonn

Author

Massimo Kofler, Apr 23 2023

Status

approved