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A158338 Composite numbers k such that k - number of divisors of k = prime. 0
6, 15, 16, 21, 27, 33, 35, 51, 57, 65, 77, 87, 93, 105, 111, 135, 141, 143, 155, 161, 165, 177, 183, 185, 189, 201, 203, 215, 231, 237, 245, 267, 275, 285, 287, 321, 335, 341, 345, 357, 371, 375, 377, 393, 413, 425, 429, 437, 447, 453, 465, 471 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A067531. - Michel Marcus, Dec 22 2014

LINKS

Table of n, a(n) for n=1..52.

EXAMPLE

6 is composite and has 4 divisors (1, 2, 3, 6); 6 - 4 = 2, which is prime, so 6 is in the sequence.

15 is composite and has 4 divisors (1, 3, 5, 15); 15 - 4 = 11, which is prime, so 15 is in the sequence.

16 is composite and has 5 divisors (1, 2, 4, 8, 16); 16 - 5 = 11, which is prime, so 16 is in the sequence.

CROSSREFS

Cf. A000005, A000040, A002808, A035004, A067531.

Sequence in context: A199094 A009579 A114812 * A139204 A122661 A133481

Adjacent sequences:  A158335 A158336 A158337 * A158339 A158340 A158341

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Mar 16 2009, Nov 14 2009

EXTENSIONS

Extended by R. J. Mathar, May 19 2010

STATUS

approved

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Last modified June 17 22:17 EDT 2019. Contains 324200 sequences. (Running on oeis4.)