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A252478 Products of a semiprime times a larger prime. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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.

LINKS

Table of n, a(n) for n=1..60.

FORMULA

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

PROG

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

CROSSREFS

Cf. A000040, A001358, A137428.

Sequence in context: A137428 A350841 A309769 * A124318 A309780 A139703

Adjacent sequences:  A252475 A252476 A252477 * A252479 A252480 A252481

KEYWORD

nonn

AUTHOR

M. F. Hasler, Jan 02 2015

STATUS

approved

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Last modified October 3 18:24 EDT 2022. Contains 357237 sequences. (Running on oeis4.)