The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A064507 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A064507

Numbers of more than one digit that yield primes when cast in their own base.
(history; published version)

#16 by Joerg Arndt at Sun Dec 04 03:57:46 EST 2016

STATUS

proposed

approved

#15 by Michel Marcus at Sun Dec 04 03:45:04 EST 2016

STATUS

editing

proposed

#14 by Michel Marcus at Sun Dec 04 03:45:00 EST 2016

PROG

(PARI) isok(n) = (n>=10) && isprime(fromdigits(digits(n), n)); \\ Michel Marcus, Dec 04 2016

#13 by Michel Marcus at Sun Dec 04 03:43:12 EST 2016

PROG

(PARI) isok(n) = isprime(fromdigits(digits(n), n)); \\ Michel Marcus, Dec 04 2016

STATUS

proposed

editing

#12 by Robert Israel at Sun Dec 04 03:38:30 EST 2016

STATUS

editing

proposed

#11 by Robert Israel at Sun Dec 04 03:36:26 EST 2016

CROSSREFS

Cf. A064508. Contained in A054684.

STATUS

proposed

editing

#10 by Robert Israel at Sun Dec 04 03:31:37 EST 2016

STATUS

editing

proposed

Discussion

Sun Dec 04

03:32

Robert Israel: It's not clear what 2, 3, 5 or 7 yield when cast in their own base.

#9 by Robert Israel at Sun Dec 04 03:28:22 EST 2016

EXTENSIONS

Name corrected by Robert Israel, Dec 04 2016

#8 by Robert Israel at Sun Dec 04 03:27:48 EST 2016

NAME

Numbers of more than one digit that yield primes when cast in their own base.

COMMENTS

All terms are coprime to 10. - Robert Israel, Dec 04 2016

LINKS

Robert Israel, <a href="/A064507/b064507.txt">Table of n, a(n) for n = 1..10000</a>

MAPLE

filter:= proc(n) local L, i;

L:= convert(n, base, 10);

isprime(add(L[i]*n^(i-1), i=1..nops(L)))

end proc:

select(filter, [seq(i, i=11..2000, 2)]); # Robert Israel, Dec 04 2016

STATUS

approved

editing

#7 by Ralf Stephan at Sun Oct 20 02:57:50 EDT 2013

STATUS

proposed

approved