A032612 -id:A032612 - cp's OEIS frontend

A032622 Numbers k such that k concatenated with k+7 is a prime.

2, 6, 20, 26, 30, 36, 44, 60, 62, 66, 74, 80, 86, 1004, 1034, 1046, 1086, 1094, 1104, 1136, 1142, 1194, 1200, 1206, 1214, 1224, 1250, 1262, 1266, 1290, 1292, 1296, 1320, 1326, 1332, 1346, 1350, 1352, 1356, 1364, 1370, 1380, 1404, 1416, 1434, 1472, 1496

Offset: 1

Patrick De Geest, May 15 1998

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

Cf. A032612.

filter:= n -> isprime(n * 10^(1+ilog10(n+7)) + n + 7):
select(filter, [seq(i,i=2..10000,2)]); # Robert Israel, May 13 2025

A032630 Primes that are concatenations of n with n + 7.

Original entry on oeis.org

29, 613, 2027, 2633, 3037, 3643, 4451, 6067, 6269, 6673, 7481, 8087, 8693, 10041011, 10341041, 10461053, 10861093, 10941101, 11041111, 11361143, 11421149, 11941201, 12001207, 12061213, 12141221, 12241231, 12501257

Offset: 1

Patrick De Geest, May 15 1998

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

Cf. A032612, A032622.

Select[Table[FromDigits[Join[IntegerDigits[n],IntegerDigits[n+7]]],{n,1500}],PrimeQ] (* Harvey P. Dale, Sep 20 2016 *)

Edited by Charles R Greathouse IV, Apr 28 2010

cp's OEIS Frontend

A032622 Numbers k such that k concatenated with k+7 is a prime.

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