A123200 Numbers k such that 1000000*k-1 and 1000000*k+1 are twin primes.

24, 30, 198, 345, 348, 432, 438, 471, 492, 609, 669, 774, 777, 858, 864, 1032, 1083, 1125, 1218, 1395, 1536, 1824, 1914, 1929, 2088, 2139, 2301, 2334, 2376, 2418, 2448, 2460, 2544, 2763, 2832, 2970, 3021, 3297, 3369, 3384, 3495, 3528, 3540, 3633, 3777

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..2000

Example

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

Maple

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

Mathematica

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 *)

Crossrefs

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

Sequence in context: A348630 A067952 A239801 * A167307 A161378 A206448

Adjacent sequences: A123197 A123198 A123199 * A123201 A123202 A123203

Keyword

easy,nonn,less

Author

Jonathan Vos Post, Nov 05 2006

Extensions

More terms from Emeric Deutsch, Nov 16 2006

Status

approved