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A051228
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Numbers m such that the Bernoulli number B_m has denominator 42.
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32
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6, 114, 186, 258, 354, 402, 426, 474, 582, 654, 762, 834, 894, 942, 978, 1002, 1158, 1182, 1194, 1266, 1338, 1362, 1374, 1614, 1842, 1902, 2022, 2094, 2118, 2166, 2274, 2298, 2334, 2406, 2454, 2526, 2598, 2634, 2694, 2742, 2778, 2874, 2922, 2994, 3126
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OFFSET
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1,1
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COMMENTS
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From the von Staudt-Clausen theorem, denominator(B_{2*m}) = product of primes p such that (p-1)|2*m.
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REFERENCES
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B. C. Berndt, Ramanujan's Notebooks Part IV, Springer-Verlag, see p. 75.
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LINKS
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FORMULA
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MATHEMATICA
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Position[BernoulliB[Range[3200]], _?(Denominator[#]==42&)]//Flatten (* Harvey P. Dale, Jul 02 2018 *)
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PROG
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(Perl) @p=(2, 3, 5, 7); @c=(4); $p=7; for($n=6; $n<=3126; $n+=6){while($p<$n+1){$p+=2; next if grep$p%$_==0, @p; push@p, $p; push@c, $p-1; }print"$n, "if!grep$n%$_==0, @c; }print"\n"
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CROSSREFS
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KEYWORD
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nonn,nice,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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