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A086554
a(1) = 1; for n>1, a(n) = smallest number not included earlier such that each P+1 is prime, where P is the product of an (n-1)-set from the previous n terms.
0
1, 2, 6, 23, 370, 1056, 36695, 491942, 23005823
OFFSET
1,2
COMMENTS
Conjecture: sequence is finite.
No more terms < 166890000. - David Wasserman, Apr 19 2005
EXAMPLE
a(4) = 23 as 1*2*6+1, 2*6*23+1, 1*6*23+1 and 1*2*23+1 (i.e. 13, 277, 139 and 47) all are primes.
CROSSREFS
Sequence in context: A364791 A020122 A327426 * A213324 A007672 A322255
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Aug 29 2003
EXTENSIONS
Corrected and extended by David Wasserman, Apr 19 2005
STATUS
approved