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A281793
The largest prime factor of (1+n)*(1+n^2).
2
1, 2, 5, 5, 17, 13, 37, 5, 13, 41, 101, 61, 29, 17, 197, 113, 257, 29, 19, 181, 401, 17, 97, 53, 577, 313, 677, 73, 157, 421, 53, 37, 41, 109, 89, 613, 1297, 137, 17, 761, 1601, 29, 353, 37, 149, 1013, 73, 17, 461, 1201, 61, 1301, 541, 281, 2917, 89, 3137, 29
OFFSET
0,2
LINKS
FORMULA
a(n) = max( A006530(n+1), A014442(n)).
a(n) = A006530(A281660(n)).
MAPLE
A281793 := proc(n)
A006530((1+n)*(1+n^2)) ;
end proc:
seq(A281793(n), n=0..60) ;
MATHEMATICA
Table[Max[Transpose[FactorInteger[(1 + n) (1 + n^2)]][[1]]], {n, 0, 60}] (* Vincenzo Librandi, Jun 03 2017 *)
PROG
(Magma) [#f eq 0 select 1 else f[ #f][1] where f is Factorization((1+n)*(1+n^2)): n in [0..60]]; // Vincenzo Librandi, Jun 03 2017
(PARI) a(n) = if (n==0, 1, my(f=factor((1+n)*(1+n^2))); vecmax(f[, 1])); \\ Michel Marcus, Jun 03 2017; corrected Jun 13 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Jan 30 2017
STATUS
approved