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A108107 Numbers n such that the string 1123n is the decimal expansion of a prime number. 0
9, 27, 31, 37, 39, 49, 61, 63, 97, 127, 151, 181, 189, 211, 217, 219, 231, 247, 267, 279, 303, 307, 319, 327, 349, 351, 361, 379, 391, 399, 403, 427, 429, 439, 477, 483, 487, 501, 511, 517, 531, 541, 553, 561, 567, 589, 597, 601, 621, 631, 637, 651, 667 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

11 and 23 are primes.

LINKS

Table of n, a(n) for n=1..53.

EXAMPLE

9 is in the sequence because 11239 is prime.

63 is in the sequence because 112363 is prime.

127 is in the sequence because 1123127 is prime.

MAPLE

a:=proc(n) local z: z:=nops(convert(n, base, 10)): if isprime(1123*10^z+n)=true then n else fi end: seq(a(n), n=1..750); (Deutsch)

PROG

(MAGMA) [ n: n in [1..700] | IsPrime(Seqint(Intseq(n) cat [3, 2, 1, 1])) ];

CROSSREFS

Cf. A107645, A107644.

Sequence in context: A022701 A276003 A255343 * A216168 A036303 A116455

Adjacent sequences:  A108104 A108105 A108106 * A108108 A108109 A108110

KEYWORD

nonn,base

AUTHOR

Parthasarathy Nambi, Jun 25 2005

EXTENSIONS

More terms from Emeric Deutsch, Jul 02 2005

STATUS

approved

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Last modified June 25 09:48 EDT 2019. Contains 324347 sequences. (Running on oeis4.)