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A160518 List of pairs of twin primes of the form 2k^3 +- 1. 2

%I #13 Dec 28 2019 07:48:29

%S 431,433,18521,18523,1940597,1940599,3455999,3456001,30876497,

%T 30876499,88723727,88723729,105468749,105468751,164625749,164625751,

%U 431999999,432000001,451733057,451733059,615093749,615093751,746495999,746496001,1039436927,1039436929

%N List of pairs of twin primes of the form 2k^3 +- 1.

%C k is always divisible by 3. For the 5 pairs listed, k = 6, 21, 99, 120 and 249 (see A151612).

%H Amiram Eldar, <a href="/A160518/b160518.txt">Table of n, a(n) for n = 1..10000</a>

%e 6^3 = 216; 216*2 = 432; both 431 and 433 are prime.

%p isA001359 := proc(n) RETURN(isprime(n) and isprime(n+2)) ; end: for n from 1 to 1000 do twon3 := 2*n^3 ; if isA001359(twon3-1) then printf("%d,%d,",twon3-1,twon3+1) ; fi; od: # _R. J. Mathar_, May 29 2009

%t s = Select[54*Range[300]^3, And @@ PrimeQ[# + {-1, 1}] &]; Flatten @

%t Transpose @ {s - 1, s + 1} (* _Amiram Eldar_, Dec 28 2019 *)

%Y Cf. A151612.

%K nonn

%O 1,1

%A Howard Berman (howard_berman(AT)hotmail.com), May 16 2009

%E More terms from _R. J. Mathar_, May 29 2009

%E More terms from _Amiram Eldar_, Dec 28 2019

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Last modified July 23 23:47 EDT 2024. Contains 374575 sequences. (Running on oeis4.)