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A082296
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Solutions to 13^x+17^x == 19 mod 23.
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1
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12, 20, 34, 42, 56, 64, 78, 86, 100, 108, 122, 130, 144, 152, 166, 174, 188, 196, 210, 218, 232, 240, 254, 262, 276, 284, 298, 306, 320, 328, 342, 350, 364, 372, 386, 394, 408, 416, 430, 438, 452, 460, 474, 482, 496, 504, 518, 526, 540, 548, 562, 570, 584
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OFFSET
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1,1
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LINKS
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FORMULA
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Numbers of the form 11*n+1 with n odd or 11*n-2 with n even.
a(n) = (-1-3*(-1)^n+22*n)/2.
a(n) = a(n-1)+a(n-2)-a(n-3) for n>3.
G.f.: 2*x*(6+4*x+x^2) / ((1-x)^2*(1+x)).
(End)
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MATHEMATICA
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PROG
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(PARI) anpbn(n) = { for(x=1, n, if((13^x+17^x-19)%23==0, print1(x", "))) }
(Magma) [IsOdd(n) select 11*n+1 else 11*n-2: n in [1..60]]; // Vincenzo Librandi, Jun 09 2016
(PARI) Vec(2*x*(6+4*x+x^2)/((1-x)^2*(1+x)) + O(x^100)) \\ Colin Barker, Jun 09 2016
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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