A370395 Numbers k that are neither squarefree nor prime powers sandwiched between twin primes.

12, 18, 60, 72, 108, 150, 180, 192, 198, 228, 240, 270, 312, 348, 420, 432, 522, 600, 660, 810, 828, 882, 1020, 1032, 1050, 1062, 1092, 1152, 1278, 1320, 1428, 1452, 1488, 1608, 1620, 1668, 1788, 1872, 1932, 1950, 1998, 2028, 2088, 2112, 2142, 2268, 2340, 2550

Offset

1,1

Comments

Contains A113839 \ {4}.

This sequence contains 1062, 1278, 1608 while A258838 does not; A258838 includes 4, 6, 30, 42, 462, 570, etc.

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Formula

Intersection of A014574 and A126706.

Example

The number 12 is neither squarefree nor a prime power but comes between primes 11 and 13.
The number 30 is squarefree, though it comes between primes 29 and 31, it is not in the sequence.

Mathematica

Select[1 + Select[Prime@ Range[100], PrimeQ[# + 2] &], Nor[SquareFreeQ[#], PrimePowerQ[#]] &]

Crossrefs

Cf. A001359, A006512, A014574, A113839, A126706, A258838.

Sequence in context: A341039 A279369 A119147 * A226176 A177426 A232384

Adjacent sequences: A370392 A370393 A370394 * A370396 A370397 A370398

Keyword

nonn,easy

Author

Michael De Vlieger, Mar 27 2024

Status

approved