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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 Table of n, a(n) for n=1..6. 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 Adjacent sequences: A144672 A144673 A144674 * A144676 A144677 A144678 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.)