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A265423
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(-1)^n + 50*floor(3n/2) - 100*floor(n/4).
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2
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1, 49, 151, 199, 201, 249, 351, 399, 401, 449, 551, 599, 601, 649, 751, 799, 801, 849, 951, 999, 1001, 1049, 1151, 1199, 1201, 1249, 1351, 1399, 1401, 1449, 1551, 1599, 1601, 1649, 1751, 1799, 1801, 1849, 1951, 1999, 2001, 2049, 2151, 2199, 2201, 2249, 2351, 2399, 2401, 2449, 2551, 2599, 2601, 2649, 2751, 2799, 2801
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OFFSET
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0,2
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COMMENTS
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Also: solutions to b^2 = 1 mod 400. Occurs in the context of a problem concerning integer-valued percentages, see link.
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LINKS
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R. Israel, in reply to E. Angelini, Percentages, SeqFan list, Dec 7, 2015.
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FORMULA
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G.f.: (1+48*x+102*x^2+48*x^3+x^4)/(1-x-x^4+x^5). - Robert Israel, Dec 08 2015
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MAPLE
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seq((-1)^n + 50*floor(3*n/2) - 100*floor(n/4), n=0..100); # Robert Israel, Dec 08 2015
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PROG
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(PARI) A265423(n)=(-1)^n+n*3\2*50-n\4*100
(PARI) is_A265423(n)=Mod(n, 400)^2==1
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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