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A193330 Number of prime factors of n^2 + 1, counted with multiplicity. 9
0, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 2, 2, 3, 1, 2, 1, 3, 3, 2, 1, 3, 2, 3, 1, 2, 1, 3, 2, 2, 2, 3, 3, 3, 2, 2, 1, 3, 3, 2, 1, 3, 2, 4, 2, 2, 2, 4, 2, 2, 2, 2, 2, 3, 1, 3, 1, 5, 2, 2, 2, 2, 2, 3, 2, 2, 1, 3, 4, 2, 3, 2, 3, 4, 1, 3, 2, 3, 2, 2, 2, 3, 3, 4, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

a(n) is also the number of terms, counted with multiplicity, in a prime factorization of n + i in the ring of Gaussian integers. - Jason Kimberley, Dec 17 2011

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 0..10000

MATHEMATICA

A193330[n_Integer] := PrimeOmega[n^2 + 1]; A193330 /@ Range[0, 100]

PrimeOmega/@(Range[0, 90]^2+1) (* Harvey P. Dale, Apr 03 2019 *)

PROG

(PARI) a(n)=bigomega(n^2+1) \\ Charles R Greathouse IV, Jul 23, 2011

CROSSREFS

Cf. A046051, A054992, A193295.

Sequence in context: A204893 A251717 A057217 * A147810 A305302 A055181

Adjacent sequences:  A193327 A193328 A193329 * A193331 A193332 A193333

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jul 22 2011

STATUS

approved

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Last modified October 23 22:28 EDT 2019. Contains 328373 sequences. (Running on oeis4.)