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A075766 Numbers n such that A007923(n) is prime. 0
2, 7, 8, 10, 17, 20, 25, 28, 31, 38, 61, 62, 355, 4690, 4772 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

SDS(355) certified prime with Primo.

No more terms <= 8000. - XU Pingya, May 30 2017

LINKS

Table of n, a(n) for n=1..15.

J. Earls, Some Results Concerning the Smarandache Deconstructive Sequence, Smarandache Notions Journal, Volume 14 Issue 1, January 2004, Pages 222-226 .

PROG

(PARI) isok(n) = my(m=(n*(n+1)/2-1)%9+1); isprime(sum(k=0, n-1, 10^k*((m-k-1)%9+1))); \\ Michel Marcus, May 30 2017

CROSSREFS

Cf. A007923.

Sequence in context: A039005 A022431 A047525 * A258823 A226612 A005538

Adjacent sequences:  A075763 A075764 A075765 * A075767 A075768 A075769

KEYWORD

more,nonn

AUTHOR

Jason Earls, Oct 09 2002

EXTENSIONS

a(14)-a(15) from XU Pingya, May 30 2017

STATUS

approved

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Last modified April 23 06:08 EDT 2019. Contains 322381 sequences. (Running on oeis4.)