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A266512
Smallest prime starting a (nonsingular) symmetric n-tuplet of the shortest span (=A266511(n)).
10
2, 3, 47, 5, 18713, 7, 12003179, 17, 1480028129, 13, 1542186111157, 41280160361347, 660287401247633, 10421030292115097, 3112462738414697093, 996689250471604163, 258406392900394343851
OFFSET
1,1
COMMENTS
A similar sequence that allows singular symmetric n-tuples is given in A266583.
a(18) <= 824871967574850703732309 (Jaroslaw Wroblewski)
a(20) <= 824871967574850703732303 (Natalia Makarova and Jaroslaw Wroblewski)
a(19) <= 9425346484752129657862217 & a(19) > 7.8e24. - Dmitry Petukhov, Jan 06 2025
LINKS
N. Makarova and Carlos Rivera, Problem 62. Symmetric k-tuples of consecutive primes, The Prime Puzzles & Problems Connection.
FORMULA
a(n) = A000040(A266584(n)).
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
Max Alekseyev, Dec 30 2015
EXTENSIONS
a(1)-a(10) from Natalia Makarova
a(11)-a(14), a(16) from Dmitry Petukhov
a(15), a(17) from Jaroslaw Wroblewski
STATUS
approved