Search: id:A122900
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%I A122900
%S A122900 5,13,337,41,61,3697,113,10657,181,2211377674535255285545615254209921,
               1,
%T A122900 313,66977,421,1,149057,613,1,761,1,4441930186581050471617,1013,
%U A122900 188386299457,1201,1301,988417,1146097,1,1741,1861,1972097,2113,2522257
%N A122900 Minimum prime of the form (n^k + (n+1)^k) for k>1, or 1 if such prime 
               does not exist or if it is still not found.
%C A122900 Currently a(n) = 1 for n = {11,15,18,20,28,44,46,49,51,52,53,55,57,58,
               61,62,64,71,73,77,81,83,91,92,94,...}. All n<100 and 1<k<2^10 are 
               checked. All a(n) that are not equal to 1 have a form n^(2^m) + (n+1)^(2^m). 
               The exponents m(n) are listed in A122901[n] = { 1,1,2,1,1,2,1,2,1,
               5,0,1,2,1,0,2,1,0,1,0, 4,1,3,1,1,2,2,0,1,1,2,1,2,1,1,2,2,2,1,2, 4,
               1,2,0,4,0,1,2,0,1,0,0,0,2,0,4,0,0,9,1, 0,0,2,0,1,3,2,2,1,1,0,1,0,
               2,4,3,0,2,1,4, 0,1,0,1,1,8,1,2,2,1,0,0,4,0,6,4,1,2,1,1,...}. The 
               first occurrence of exponent m>0 in A122901[n] is listed in A122902[m] 
               ={1,3,23,21,10,95,...}.
%e A122900 a(1) = 5 because 1^2 + 2^2 = 5 is prime.
%e A122900 a(2) = 13 because 2^2 + 3^2 = 13 is prime.
%e A122900 a(3) = 337 because 3^4 + 4^4 = 337 is prime but 3^3 + 4^3 = 91 and 3^2 
               + 4^2 = 25 are composite.
%e A122900 a(11) = 1 because prime of the form 11^k + 12^k is not found for 1<k<2000.
%Y A122900 Cf. A122901, A122902, A080208.
%Y A122900 Sequence in context: A124878 A085554 A067135 this_sequence A145557 A012033 
               A007540
%Y A122900 Adjacent sequences: A122897 A122898 A122899 this_sequence A122901 A122902 
               A122903
%K A122900 hard,nonn
%O A122900 1,1
%A A122900 Alexander Adamchuk (alex(AT)kolmogorov.com), Sep 18 2006

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