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 A060975 Irregular primes with irregularity index three. 11
 491, 617, 647, 1151, 1217, 1811, 1847, 2939, 3833, 4003, 4657, 4951, 6763, 7687, 8831, 9011, 10463, 10589, 12073, 13217, 14533, 14737, 14957, 15287, 15787, 15823, 16007, 17681, 17863, 18713, 18869, 20533, 20939, 24019, 24659, 25153, 26561 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS T. D. Noe, Table of n, a(n) for n=1..9824 (from Buhler et al.) J. Buhler, R. Crandall, R. Ernvall, T. Metsankyla and M. A. Shokrollahi, Irregular Primes and Cyclotomic Invariants to 12 Million, J. Symbolic Computation 31, 2001, 89-96. MATHEMATICA Do[p = Prime[n]; k = 1; c = 0; While[ 2*k < p - 3, If[ Mod[ Numerator[ BernoulliB[2*k]], p] == 0, c++ ]; k++ ]; If[ c == 3, Print[p]], {n, 3, 1000} ] Do[p = Prime@n; k = 1; c = 0; While[ 2*k < p - 3, If[ Mod[ Numerator[ BernoulliB[2*k]], p] == 0, c++ ]; k++ ]; If[ c == 3, Print@p], {n, 3, 13887} ] CROSSREFS Cf. A000928, A000367, A060974, A060975, A073276 and A073277. Sequence in context: A056052 A051115 A273809 * A180457 A271664 A082079 Adjacent sequences:  A060972 A060973 A060974 * A060976 A060977 A060978 KEYWORD nonn AUTHOR Robert G. Wilson v, Jul 22 2002 EXTENSIONS Extended by Robert G. Wilson v, Sep 20 2006 STATUS approved

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Last modified August 18 19:41 EDT 2017. Contains 290762 sequences.