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A097480 Positive integers n such that 2n-15 is prime. 21
9, 10, 11, 13, 14, 16, 17, 19, 22, 23, 26, 28, 29, 31, 34, 37, 38, 41, 43, 44, 47, 49, 52, 56, 58, 59, 61, 62, 64, 71, 73, 76, 77, 82, 83, 86, 89, 91, 94, 97, 98, 103, 104, 106, 107, 113, 119, 121, 122, 124, 127, 128, 133, 136, 139, 142, 143, 146, 148, 149, 154, 161, 163 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Solutions of the equation (2*n-15)'=1, where n' is the arithmetic derivative of n. - Paolo P. Lava, Nov 15 2012

LINKS

Shawn A. Broyles, Table of n, a(n) for n = 1..1000

FORMULA

Half of p+15 where p is a prime greater than 2.

MATHEMATICA

(Prime[Range[2, 100]]+15)/2 (* Vladimir Joseph Stephan Orlovsky, Feb 08 2010 *)

PROG

(PARI) is(n)=isprime(2*n-15) \\ Charles R Greathouse IV, Jul 12 2016

CROSSREFS

Cf. A000040, A098602, A098603.

Numbers n such that 2n+k is prime: A005097 (k=1), A067076 (k=3), A089038 (k=5), A105760 (k=7), A155722 (k=9), A101448 (k=11), A153081 (k=13), A089559 (k=15), A173059 (k=17), A153143 (k=19).

Numbers n such that 2n-k is prime: A006254 (k=1), A098090 (k=3), A089253 (k=5), A089192 (k=7), A097069 (k=9), A097338 (k=11), A097363 (k=13), this sequence (k=15), A098605 (k=17), A097932 (k=19).

Sequence in context: A173147 A293761 A253881 * A034068 A045550 A031047

Adjacent sequences:  A097477 A097478 A097479 * A097481 A097482 A097483

KEYWORD

easy,nonn

AUTHOR

Douglas Winston (douglas.winston(AT)srupc.com), Sep 19 2004

STATUS

approved

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Last modified October 15 15:14 EDT 2019. Contains 328030 sequences. (Running on oeis4.)