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A049238
a(n) is the number of divisors of prime(n) - 2.
0
1, 2, 2, 3, 2, 4, 2, 4, 4, 2, 4, 4, 2, 6, 4, 4, 2, 4, 4, 2, 4, 5, 4, 4, 6, 2, 8, 2, 4, 4, 4, 8, 2, 6, 2, 4, 4, 8, 6, 4, 2, 8, 2, 8, 2, 4, 4, 9, 2, 8, 4, 2, 4, 8, 6, 4, 2, 6, 6, 2, 4, 4, 4, 2, 12, 4, 4, 8, 2, 8, 8, 4, 4, 4, 4, 6, 4, 8, 4, 4, 2, 8, 2, 4, 9, 4, 8, 8, 2, 8, 6, 4, 4, 4, 4, 6, 4, 2, 6, 4, 8, 8, 10
OFFSET
2,2
FORMULA
a(n) = A000005(prime(n) - 2).
EXAMPLE
prime(23)=83, so a(23) = A000005(83-2) = A000005(81) = 5.
MATHEMATICA
DivisorSigma[0, #]&/@(Prime[Range[2, 110]]-2) (* Harvey P. Dale, Jan 11 2019 *)
PROG
(PARI) a(n) = numdiv(prime(n)-2); \\ Michel Marcus, May 14 2018
CROSSREFS
Sequence in context: A326641 A144372 A182861 * A001616 A257599 A366620
KEYWORD
nonn
AUTHOR
EXTENSIONS
Offset corrected by Jon E. Schoenfield, May 13 2018
STATUS
approved