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 A123200 Numbers k such that 1000000*k-1 and 1000000*k+1 are twin primes. 1
 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 (list; graph; refs; listen; history; text; internal format)
 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: A109321 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

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Last modified May 14 12:37 EDT 2021. Contains 343884 sequences. (Running on oeis4.)