A164314 - OEIS

A164314

Largest prime factor of n^2 - 2.

2, 7, 7, 23, 17, 47, 31, 79, 7, 17, 71, 167, 97, 223, 127, 41, 23, 359, 199, 439, 241, 31, 41, 89, 337, 727, 23, 839, 449, 137, 73, 1087, 577, 1223, 647, 1367, 103, 31, 47, 73, 881, 1847, 967, 17, 151, 2207, 1151, 2399, 1249, 113, 193, 401, 47, 3023, 1567, 191

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OFFSET

2,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 2..10000

FORMULA

a(n) = A006530(A008865(n)).

MAPLE

a:= n-> max(numtheory[factorset](n^2-2)):

seq(a(n), n=2..60); # Alois P. Heinz, Jul 22 2017

MATHEMATICA

Table[FactorInteger[n^2 - 2][[-1, 1]], {n, 2, 57}] (* Michael De Vlieger, Jul 22 2017 *)