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A053609 Primes of form x^2+1 where x = LCM(1,2,...,k) for some k. 1
2, 5, 37, 176401, 129859329601, 516625648014869290354797521879383114125823989794742396526049715541246671360001 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The next term has k > 10^4, if it exists. - Amiram Eldar, Aug 23 2024
LINKS
FORMULA
a(n) = A053608(A053608(n)) = A053608(n)^2 + 1. - Amiram Eldar, Aug 23 2024
MATHEMATICA
Select[FoldList[LCM, 1, Select[Range[100], PrimePowerQ]]^2 + 1, PrimeQ] (* Amiram Eldar, Aug 23 2024 *)
CROSSREFS
Sequence in context: A222318 A084436 A210482 * A036780 A051501 A221681
KEYWORD
nonn,hard,changed
AUTHOR
Labos Elemer, Feb 09 2000
STATUS
approved

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Last modified August 31 10:25 EDT 2024. Contains 375560 sequences. (Running on oeis4.)