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A210454
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Cipolla pseudoprimes to base 2: (4^p-1)/3 for any prime p greater than 3.
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6
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341, 5461, 1398101, 22369621, 5726623061, 91625968981, 23456248059221, 96076792050570581, 1537228672809129301, 6296488643826193618261, 1611901092819505566274901, 25790417485112089060398421, 6602346876188694799461995861
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OFFSET
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1,1
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COMMENTS
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This is the case a=2 of Theorem 1 in the paper of Hamahata and Kokubun (see Links section).
Named after the Italian mathematician Michele Cipolla (1880-1947). - Amiram Eldar, Jun 15 2021
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LINKS
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Y. Hamahata and Y. Kokubun, Cipolla Pseudoprimes, Journal of Integer Sequences, Vol. 10 (2007), Article 07.8.6.
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MAPLE
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P:=proc(q)local n;
for n from 3 to q do print((4^ithprime(n)-1)/3);
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MATHEMATICA
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(4^# - 1)/3 & /@ Prime[Range[3, 15]]
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PROG
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(Magma) [(4^NthPrime(n)-1)/3: n in [3..15]];
(Maxima)
Prime(n) := block(if n = 1 then return(2), return(next_prime(Prime(n-1))))$
makelist((4^Prime(n)-1)/3, n, 3, 15);
(Haskell)
a210454 = (`div` 3) . (subtract 1) . (4 ^) . a000040 . (+ 2)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Bruno Berselli, Jan 21 2013 - proposed by Umberto Cerruti (Department of Mathematics "Giuseppe Peano", University of Turin, Italy)
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STATUS
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approved
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