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Numbers t such that t1 is prime and t is a multiple of 10.
1

%I #6 Jan 10 2017 10:54:15

%S 10,40,60,70,120,130,160,180,190,280,300,330,370,400,420,480,510,550,

%T 570,580,610,630,670,700,790,810,850,900,960,990,1030,1050,1060,1170,

%U 1180,1210,1230,1240,1260,1300,1390,1440,1510,1540,1560,1590,1600,1630,1690,1740,1830,1840,1870

%N Numbers t such that t1 is prime and t is a multiple of 10.

%H Harvey P. Dale, <a href="/A102546/b102546.txt">Table of n, a(n) for n = 1..1000</a>

%e If t=10, then t1 = 101 (prime).

%e If t=180, then t1 = 1801 (prime).

%e If t=420, then t1 = 4201 (prime).

%t Select[10*Range[200],PrimeQ[10#+1]&] (* _Harvey P. Dale_, Jan 10 2017 *)

%Y Cf. A024912.

%K nonn,base

%O 1,1

%A _Parthasarathy Nambi_, Feb 24 2005