cp's OEIS Frontend

A168385 Numbers of the form |a^b - c^d| where a, b, c and d are the first 4 primes.

%I A168385 #3 Jun 22 2011 18:11:12
%S A168385 3,76,115,194,311,318,2155,2162,16798,16799,78116,78117
%N A168385 Numbers of the form |a^b - c^d| where a, b, c and d are the first 4 primes.
%C A168385 There are 4! = 24 permutations of 4 elements, because of commutativity of |x|=|- x| sequence has 4!/2 = 12 different terms.
%C A168385 Note that two terms of sequence (3 and 311) are prime numbers.
%D A168385 Ivan Niven und H. S. Zuckermann, Einfuehrung in die Zahlentheorie, B.I. Mannheim 1976
%D A168385 Friedhelm Padberg, Elementare Zahlentheorie, Spektrum Akademischer Verlag, 2. Auflage 1991
%e A168385 (1) 3 = 2^7 - 5^3 = prime(2)
%e A168385 (2) 76 = 2 ^ 2 x 19 = 5^3 - 7^2
%e A168385 (3) 115 = 5 x 23 = 3^5 - 2^7
%e A168385 (4) 194 = 2 x 97 = 3^5 - 7^2
%e A168385 (5) 311 = 7^3 - 2^5 = prime(2^6)
%e A168385 (6) 318 = 2 x 3 x 53 = 7^3 - 5^2
%e A168385 (7) 2155 = 5 x 431 = 3^7 - 2^5
%e A168385 (8) 2162 = 2 x 23 x 47 = 3^7 - 5^2
%e A168385 (9) 16798 = 2 x 37 x 227 = 7^5 - 3^2
%e A168385 (10) 16799 = 107 x 157 = 7^5 - 2^3
%e A168385 (11) 78116 = 2 ^ 2 x 59 x 331 = 5^7 - 3^2
%e A168385 (12) 78117 = 3 x 13 x 2003 = 5^7 - 2^3
%Y A168385 Cf. A168349.
%K A168385 fini,full,nonn
%O A168385 1,1
%A A168385 Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 24 2009