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A344869
Number of distinct prime factors of n^n+1.
5
1, 1, 1, 2, 1, 3, 3, 3, 3, 4, 3, 6, 4, 5, 5, 6, 2, 3, 7, 5, 3, 6, 4, 8, 6, 7, 5, 11, 6, 7, 10, 7, 4, 11, 6, 13, 5, 7, 7, 8, 9, 6, 10, 8, 8, 14, 8, 10, 6, 7, 10, 11, 5, 8, 14, 11, 7, 13, 13, 9, 12, 8, 7, 18, 4, 12, 8, 7, 7, 16, 9, 8, 12, 4, 8, 24, 7, 9, 14, 7, 5, 12, 6, 12, 8, 13, 10, 12, 10, 6, 23, 15, 6, 9, 11, 16, 3, 8, 17, 23, 7
OFFSET
0,4
LINKS
Eric Weisstein's World of Mathematics, Sierpinski Number of the First Kind.
FORMULA
a(n) = A001221(A014566(n)).
MATHEMATICA
a[0] = 1; a[n_] := PrimeNu[n^n + 1]; Array[a, 45, 0] (* Amiram Eldar, May 31 2021 *)
PROG
(PARI) a(n) = omega(n^n+1);
(Magma) [#PrimeDivisors(n^n+1): n in [0..100]];
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 31 2021
EXTENSIONS
a(67)-a(79) from Jon E. Schoenfield, May 31 2021
a(80)-a(100) from Seiichi Manyama, May 31 2021
STATUS
approved