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A144675 Numbers n such that A090831(n) is prime. 1
1, 2, 6, 8, 10, 242 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
No further terms up to n=2540 (A090831(2540) ~ 10^7400). A090831(242) is a proved prime (in spite of the given PARI code).
Obviously all terms beyond the first must be even, so one might as well consider a(n)/2 = 1,3,4,5,121,...
LINKS
PROG
(PARI) print1(1); forstep( n=2, 3000, 2, /* n%10|print1([n]); */ ispseudoprime( sum( i=1, n, prime(i)^(n+1-i))) & print1(", "n))
CROSSREFS
Sequence in context: A185078 A214402 A166064 * A088417 A050880 A182424
KEYWORD
nonn,more,hard
AUTHOR
M. F. Hasler, Feb 02 2009, Feb 16 2009
STATUS
approved

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Last modified June 21 06:22 EDT 2024. Contains 373540 sequences. (Running on oeis4.)