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A050249 Weakly prime numbers (changing any one decimal digit always produces a composite number). 13
294001, 505447, 584141, 604171, 971767, 1062599, 1282529, 1524181, 2017963, 2474431, 2690201, 3085553, 3326489, 4393139, 5152507, 5564453, 5575259, 6173731, 6191371, 6236179, 6463267, 6712591, 7204777, 7469789, 7469797 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Tao proved that this sequence is infinite. - T. D. Noe, Mar 01 2011

LINKS

Klaus Brockhaus, Table of n, a(n) for n = 1..1317 (terms < 500000000)

Terence Tao, A remark on primality testing and decimal expansions, Journal of the Australian Mathematical Society 91:3 (2011), pp. 405-413.

Eric Weisstein's World of Mathematics, Weakly Prime

PROG

(MAGMA) IsA118118:=function(n); D:=Intseq(n); return forall{ <k, j>: k in [1..#D], j in [0..9] | j eq D[k] or not IsPrime(Seqint(S)) where S:=Insert(D, k, k, [j]) }; end function; [ p: p in PrimesUpTo(8000000) | IsA118118(p) ]; // Klaus Brockhaus, Feb 28 2011

CROSSREFS

Cf. A118118.

Cf. A137985 (analogous base 2 sequence), A186995 (weak primes in base n).

Sequence in context: A104328 A219318 A158124 * A224973 A182206 A178997

Adjacent sequences:  A050246 A050247 A050248 * A050250 A050251 A050252

KEYWORD

nonn,base

AUTHOR

Eric W. Weisstein

EXTENSIONS

Edited by Charles R Greathouse IV, Aug 02 2010

STATUS

approved

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Last modified September 2 15:16 EDT 2014. Contains 246361 sequences.