A032608 -id:A032608 - cp's OEIS frontend

A032618 Numbers k such that k concatenated with k+3 is a prime.

4, 8, 10, 16, 44, 46, 56, 58, 68, 74, 86, 94, 98, 100, 104, 106, 136, 140, 148, 154, 158, 160, 166, 176, 184, 194, 206, 230, 244, 250, 254, 260, 266, 268, 274, 286, 296, 308, 310, 328, 338, 344, 346, 370, 380, 388, 410, 416, 430, 434, 436, 440, 448, 460

Offset: 1

Patrick De Geest, May 15 1998

Robert Israel, Table of n, a(n) for n = 1..10000

Cf. A032608.

filter:= n -> isprime(n*(10^(1+ilog10(n+3))+1)+3):
select(filter, [seq(i,i=4..1000,2)]); # Robert Israel, Nov 14 2019

Select[Range[500],PrimeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ #+3]]]]&] (* Harvey P. Dale, Jul 19 2011 *)

A032626 Primes that are concatenations of n with n + 3.

Original entry on oeis.org

47, 811, 1013, 1619, 4447, 4649, 5659, 5861, 6871, 7477, 8689, 9497, 98101, 100103, 104107, 106109, 136139, 140143, 148151, 154157, 158161, 160163, 166169, 176179, 184187, 194197, 206209, 230233, 244247, 250253, 254257

Offset: 1

Patrick De Geest, May 15 1998

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

Cf. A032608, A032618.

Select[Table[FromDigits[Join[IntegerDigits[n],IntegerDigits[n+3]]],{n,300}],PrimeQ] (* Harvey P. Dale, Mar 25 2015 *)

cp's OEIS Frontend

A032618 Numbers k such that k concatenated with k+3 is a prime.

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