cp's OEIS Frontend

A168349 Numbers of the form a^b + c^d where a, b, c and d are the first 4 primes.

%I A168349 #5 Oct 25 2015 13:38:18
%S A168349 174,253,292,368,371,375,2212,2219,16815,16816,78133,78134
%N A168349 Numbers of the form a^b + c^d where a, b, c and d are the first 4 primes.
%C A168349 There are 4! = 24 permutations of 4 elements, because of commutativity of addition the sequence has 12 different terms.
%C A168349 Note that all terms are composite.
%D A168349 Leonard E. Dickson: History of the Theory of numbers, vol. I, Dover Publications 2005
%D A168349 Friedhelm Padberg, Elementare Zahlentheorie, Spektrum Akademischer Verlag, 2. Auflage 1991
%e A168349 (1) 174 = 2 x 3 x 29 = 5^3 + 7^2
%e A168349 (2) 253 = 11 x 23 = 2^7 + 5^3
%e A168349 (3) 292 = 2 ^ 2 x 73 = 3^5 + 7^2
%e A168349 (4) 368 = 2^4 x 23 = 5^2 + 7^3
%e A168349 (5) 371 = 7 x 53 = 2^7 + 3^5
%e A168349 (6) 375 = 3 x 5 ^ 3 = 2^5 + 7^3
%e A168349 (7) 2212 = 2 ^ 2 x 7 x 79 = 3^7 + 5^2
%e A168349 (8) 2219 = 7 x 317 = 2^5 + 3^7
%e A168349 (9) 16815 = 3 x 5 x 19 x 59 = 2^3 + 7^5
%e A168349 (10) 16816 = 2 ^ 4 x 1051 = 3^2 + 7^5
%e A168349 (11) 78133 = 11 x 7103 = 2^3 + 5^7
%e A168349 (12) 78134 = 2 x 7 x 5581 = 3^2 + 5^7
%t A168349 Union[#[[1]]^#[[2]]+#[[3]]^#[[4]]&/@Permutations[Prime[Range[4]]]] (* _Harvey P. Dale_, Oct 25 2015 *)
%K A168349 fini,full,nonn
%O A168349 1,1
%A A168349 Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 23 2009, Nov 24 2009