A123200 - OEIS

%I #11 May 10 2019 23:38:44

%S 24,30,198,345,348,432,438,471,492,609,669,774,777,858,864,1032,1083,

%T 1125,1218,1395,1536,1824,1914,1929,2088,2139,2301,2334,2376,2418,

%U 2448,2460,2544,2763,2832,2970,3021,3297,3369,3384,3495,3528,3540,3633,3777

%N Numbers k such that 1000000*k-1 and 1000000*k+1 are twin primes.

%H Harvey P. Dale, <a href="/A123200/b123200.txt">Table of n, a(n) for n = 1..2000</a>

%e a(6) = 432 because 431999999 and 432000001 are primes.

%p a:=proc(n) if isprime(10^6*n-1)=true and isprime(10^6*n+1)=true then n else fi end: seq(a(n),n=1..4500); # _Emeric Deutsch_, Nov 16 2006

%t Select[Range[3800],AllTrue[#*10^6+{1,-1},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Nov 13 2017 *)

%Y Cf. A000040, A040040, A045753, A002822, A124065.

%K easy,nonn,less

%O 1,1

%A _Jonathan Vos Post_, Nov 05 2006

%E More terms from _Emeric Deutsch_, Nov 16 2006