A289866 Primes obtained from other primes by prefixing a 1.

13, 17, 113, 131, 137, 167, 173, 179, 197, 1103, 1109, 1151, 1163, 1181, 1193, 1223, 1229, 1277, 1283, 1307, 1367, 1373, 1409, 1433, 1439, 1487, 1499, 1523, 1571, 1601, 1607, 1613, 1619, 1709, 1733, 1787, 1811, 1823, 1877, 1907, 1997, 11069, 11087, 11093

Offset: 1

Author

Vincenzo Librandi, Jul 14 2017

Keywords

• nonn
• base

Examples

			131 is a term because it is a prime obtained by prefixing a 1 to the prime 31.
1409 is a term because it is a prime obtained by prefixing a 1 to the prime 409.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..2170

Crossrefs

Cf. A039790 (primes prefixed by 1).

Cf. primes obtained from other primes by prefixing a k: this sequence (k=1), A165243 (k=2), A165292 (k=3), A165444 (k=4), A165555 (k=5), A289867 (k=6), A167187 (k=7), A290407 (k=8).

Programs

Magma

[k: p in PrimesUpTo(1500) | IsPrime(k) where k is Seqint(Intseq(p) cat [1])];

Mathematica

Select[Table[FromDigits[Join[IntegerDigits[1], IntegerDigits[Prime[n]]]], {n, 300}], PrimeQ]
Select[Table[10^IntegerLength[p]+p,{p,Prime[Range[200]]}],PrimeQ] (* Harvey P. Dale, Oct 17 2021 *)