A050713 Inserting a digit '3' between adjacent digits of n makes a prime.

11, 17, 19, 23, 29, 31, 37, 41, 43, 49, 61, 73, 79, 89, 97, 103, 107, 131, 137, 139, 157, 163, 181, 191, 193, 209, 211, 233, 239, 241, 251, 257, 259, 263, 281, 283, 307, 331, 353, 367, 379, 391, 397, 407, 413, 427, 431, 463, 493, 521, 523, 529, 547, 563, 569

Offset: 1

Author

Patrick De Geest, Aug 15 1999

Keywords

• nonn
• base

Examples

			407 becomes 4(3)0(3)7 which is prime 43037.
		

Links

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

Crossrefs

Cf. A050674, A050711, A050712, A050714, A050715, A050716, A050717, A050718, A050719.

Programs

Mathematica

Select[Range[10,600],PrimeQ[FromDigits[Riffle[IntegerDigits[#],3]]]&] (* Harvey P. Dale, Dec 23 2023 *)