A084726 - OEIS

%I #10 Aug 25 2014 12:20:34

%S 1,1,1,3,7,5,5,5,7,7,1,7,11,3,41,15,21,25,11,3,69,5,87,35,17,27,1,27,

%T 5,9,3,53,9,21,25,9,1,57,15,19,1,21,191,19,25,149,83,23,7,121,205,133,

%U 185,39,43,23,9,9,3,257,109,25,107,65,19,43,97,115,197,89,109,55,1,161,61

%N Smallest common difference of the arithmetic progression of length n, beginning with 1 whose product of first n terms + 1 is a prime.

%C Obviously all the terms are odd.

%e The arithmetic progression in triangular form:

%e 1

%e 1 2

%e 1 2 3

%e 1 4 7 10

%e 1 8 15 22 29

%e 1 6 11 16 21 26

%e ...

%Y Cf. A084727.

%K nonn

%O 1,4

%A _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 13 2003

%E More terms from _David Wasserman_, Jan 03 2005

%E Example triangle corrected by _Nathaniel Johnston_, Jun 25 2011