A252478 Products of a semiprime times a larger prime.

20, 28, 42, 44, 52, 66, 68, 76, 78, 92, 99, 102, 110, 114, 116, 117, 124, 130, 138, 148, 153, 164, 170, 171, 172, 174, 186, 188, 190, 207, 212, 222, 230, 236, 238, 244, 246, 255, 258, 261, 266, 268, 279, 282, 284, 285, 290, 292, 310, 316, 318, 322, 332, 333, 345, 354, 356, 366, 369, 370

Offset: 1

Author

M. F. Hasler, Jan 02 2015

Keywords

• nonn

Comments

Primitive elements of the sequence A137428 of numbers which have a composite divisor smaller than their largest prime factor: That sequence consists of all multiples of the terms of this sequence.

Crossrefs

Cf. A000040, A001358, A137428.

Programs

PARI

is(n)={bittest(12,#f=factor(n)~) && f[1,#f]^2>n && setsearch([[2,1],[1,1,1]], f[2,])}

Formula

A252478 = { s*p ; s in A001358, p in A000040 and p > s }.