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A073649 Define the composite field of a prime q to be f(q) = (t,s) if p, q, r are three consecutive primes and q-p = t and r-q = s. This is a sequence of primes q with field (4,2). 6

%I

%S 11,17,41,71,101,107,197,227,281,311,461,617,827,857,881,1091,1301,

%T 1427,1451,1487,1667,1697,1787,1871,1877,1997,2087,2141,2381,2687,

%U 2711,2801,3167,3257,3461,3467,3851,4157,4517,4787,5231,5417,5441,5651,5657

%N Define the composite field of a prime q to be f(q) = (t,s) if p, q, r are three consecutive primes and q-p = t and r-q = s. This is a sequence of primes q with field (4,2).

%C Solutions of the equation (n-4)' + n' + (n+2)' = 3, where n' is the arithmetic derivative of n. [_Paolo P. Lava_, Nov 09 2012].

%H Alois P. Heinz, <a href="/A073649/b073649.txt">Table of n, a(n) for n = 1..1000</a>

%t Transpose[Select[Partition[Prime[Range[1200]],3,1],Differences[#] == {4,2}&]] [[2]] (* _Harvey P. Dale_, Jul 23 2011 *)

%Y Cf. A073648, A073650.

%Y Cf. A098413, A098414.

%Y Equals A022005 + 4.

%K nonn

%O 1,1

%A _Amarnath Murthy_, Aug 09 2002

%E Corrected and extended by _Benoit Cloitre_, Aug 13 2002

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Last modified December 14 19:27 EST 2019. Contains 329987 sequences. (Running on oeis4.)