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A177748
First primes of record chains of consecutive primes such that all of them are evil (A027699).
3
3, 257, 337, 4423, 4919, 30431, 66841, 514271, 14490383, 231234569, 325923613, 640085473, 1600993259, 7180164577, 8069913503, 86933359951, 284331217637, 1128352801153, 1209935587291, 2454267258251, 2945783287813
OFFSET
1,1
COMMENTS
The first lengths of such chains of primes are: 2, 3, 5, 7, 8, 12, 16, ..., cf. A177801.
EXAMPLE
257 is the first evil prime followed by two consecutive primes (263,269) which are also evil. Thus it is record length 3.
PROG
(PARI) {l=0; sp=0; r=0; forprime( p=1, default(primelimit), if( norml2(binary(p))%2, l>r & !print1(sp", ") & r=l; l & l=0, l || sp=p; l++))} \\ M. F. Hasler, Dec 12 2010
CROSSREFS
Cf. A001969, A000069, A027697, A027699, A177798 (odious version), A177801.
Sequence in context: A203495 A051490 A232545 * A283018 A003381 A219550
KEYWORD
nonn,base,more
AUTHOR
Vladimir Shevelev, Dec 12 2010
EXTENSIONS
More terms from D. S. McNeil, Dec 12 2010
a(18)-a(21) from Amiram Eldar, Dec 09 2020
STATUS
approved