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A056102
Numbers k such that k^4 == 1 (mod 5^5).
0
1, 1068, 2057, 3124, 3126, 4193, 5182, 6249, 6251, 7318, 8307, 9374, 9376, 10443, 11432, 12499, 12501, 13568, 14557, 15624, 15626, 16693, 17682, 18749, 18751, 19818, 20807, 21874, 21876, 22943, 23932, 24999, 25001, 26068, 27057, 28124
OFFSET
1,2
FORMULA
From Chai Wah Wu, Jun 21 2020: (Start)
a(n) = a(n-1) + a(n-4) - a(n-5) for n > 5.
G.f.: x*(x^4 + 1067*x^3 + 989*x^2 + 1067*x + 1)/(x^5 - x^4 - x + 1). (End)
MATHEMATICA
x=5; Select[ Range[ 50000 ], PowerMod[ #, x-1, x^5 ]==1& ]
PROG
(PARI) for(n=1, 30000, if(n^4%5^5==1, print1(n, ", "))) \\ Hugo Pfoertner, Jun 21 2020
CROSSREFS
Sequence in context: A224457 A123211 A023078 * A218564 A234880 A218565
KEYWORD
nonn,easy
AUTHOR
Robert G. Wilson v, Jun 08 2000
STATUS
approved