A032707 - OEIS

%I #14 Aug 13 2024 11:49:38

%S 0,5,6,12,15,21,32,33,35,41,45,48,54,56,59,62,68,69,74,84,90,95,101,

%T 108,116,117,119,126,134,141,147,155,167,171,174,176,182,186,188,194,

%U 197,203,209,210,216,221,222,225,227,234,242,243,246,248,255,266

%N Numbers k such that k prefixed by '7' and followed by '1' is prime.

%H Harvey P. Dale, <a href="/A032707/b032707.txt">Table of n, a(n) for n = 1..1000</a>

%t n71Q[n_]:=PrimeQ[FromDigits[Join[{7},IntegerDigits[n],{1}]]]; Select[ Range[ 0,300],n71Q] (* _Harvey P. Dale_, Jun 20 2017 *)

%Y Cf. A032702-A032733.

%K nonn,base

%O 1,2

%A _Patrick De Geest_, May 15 1998

%E Offset changed by _Andrew Howroyd_, Aug 11 2024