A108106 Numbers n such that the string 1119n is the decimal expansion of a prime number.

7, 13, 19, 49, 53, 59, 73, 77, 97, 109, 121, 169, 179, 221, 227, 241, 269, 281, 299, 319, 323, 343, 359, 389, 397, 403, 449, 473, 523, 527, 529, 557, 577, 589, 607, 611, 623, 649, 653, 659, 673, 691, 697, 707, 733, 737, 779, 793, 799, 809, 817, 821, 823

Offset

1,1

Comments

11 and 19 are primes.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

7 is in the sequence because 11197 is prime.
73 is in the sequence because 111973 is prime.
221 is in the sequence because 1119221 is prime.

Maple

a:=proc(n) local z: z:=nops(convert(n, base, 10)): if isprime(1119*10^z+n)=true then n else fi end: seq(a(n), n=1..1000); # Emeric Deutsch, Jul 06 2005

Mathematica

Select[Range[900], PrimeQ[FromDigits[Join[{1, 1, 1, 9}, IntegerDigits[#]]]]&]  (* Harvey P. Dale, May 22 2012 *)

Prog

(Magma) [ n: n in [1..900] | IsPrime(Seqint(Intseq(n) cat [9, 1, 1, 1])) ];

Crossrefs

Cf. A107645, A107644.

Sequence in context: A073648 A298737 A109558 * A231506 A165724 A144232

Adjacent sequences: A108103 A108104 A108105 * A108107 A108108 A108109

Keyword

nonn,base

Author

Parthasarathy Nambi, Jun 25 2005

Extensions

More terms from Emeric Deutsch, Jul 06 2005

Status

approved