2,4

Three results are missing for a(7) in Eric Weisstein's World of Mathematics, they're [2, 3, 7, 43, 3263, 4051, 2558951] [2, 3, 11, 25, 29, 1097, 2753] [2, 3, 13, 25, 29, 67, 2981] [From Du, Zhao Hui, Jan 24 2010]

Table of n, a(n) for n=2..8.

Eric Weisstein's World of Mathematics, Znam's Problem

all results for a(8) [From Du, Zhao Hui, Jan 24 2010]

Cf. A075461.

Sequence in context: A217389 A123310 A058119 * A187008 A075634 A007127

Adjacent sequences: A075438 A075439 A075440 * A075442 A075443 A075444

nonn,more,hard

Eric W. Weisstein, Sep 16, 2002

Corrected a(7)-a(8) by Du, Zhao Hui, Jan 24 2010

approved