A053609 Primes of form x^2+1 where x = LCM(1,2,...,k) for some k.

2, 5, 37, 176401, 129859329601, 516625648014869290354797521879383114125823989794742396526049715541246671360001

Offset

1,1

Comments

The next term has k > 10^4, if it exists. - Amiram Eldar, Aug 23 2024

Links

Table of n, a(n) for n=1..6.

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

Cf. A049536, A046029, A051739, A051418, A051451, A053608.

Sequence in context: A222318 A084436 A210482 * A036780 A051501 A221681

Adjacent sequences: A053606 A053607 A053608 * A053610 A053611 A053612

Keyword

nonn,hard

Author

Labos Elemer, Feb 09 2000

Status

approved