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A248516
n^2+1 divided by its largest prime factor.
3
1, 1, 2, 1, 2, 1, 10, 5, 2, 1, 2, 5, 10, 1, 2, 1, 10, 25, 2, 1, 26, 5, 10, 1, 2, 1, 10, 5, 2, 17, 26, 25, 10, 13, 2, 1, 10, 85, 2, 1, 58, 5, 50, 13, 2, 29, 130, 5, 2, 41, 2, 5, 10, 1, 34, 1, 250, 5, 2, 13, 2, 5, 10, 17, 2, 1, 10, 125, 2, 169, 2, 85, 130, 1, 58
OFFSET
1,3
COMMENTS
a(n)=1 iff n^2+1 is prime (see A002496).
Conjecture: The Fibonacci numbers in the sequence are 1, 2, 5, 13, 34, 89, 233, 377, 610, 1597, 4181, 10946, 28657, 75025, 121393, 196418, ... including all of A001519.
LINKS
FORMULA
a(n) = A002522(n)/A014442(n).
a(n) = A052126(1+n^2). - R. J. Mathar, Jun 18 2015
MAPLE
A248516 := proc(n)
n^2+1 ;
%/A006530(%) ;
end proc:
seq(A248516(n), n=1..20) ; # R. J. Mathar, Jun 18 2015
MATHEMATICA
Table[(n^2 + 1)/FactorInteger[n^2 + 1][[-1, 1]], {n, 75}] (* Michael De Vlieger, Jun 19 2015 *)
PROG
(PARI) a(n) = my(x=n^2+1); my(f=factor(x)); x/f[#f~, 1]; \\ Michel Marcus, Jun 18 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Michel Lagneau, Jun 18 2015
STATUS
approved