[seqfan] Comments and corrections: A122811 and A059975
hv at crypt.org
hv at crypt.org
Fri May 21 16:51:08 CEST 2010
%N A122811 Number of prime factors (counted with multiplicity) of the smallest
odd number with exactly n divisors.
- add a comment with crossref, and correct repeated typo in crossrefs.
%N A059975 n*a(n) is the number of complex multiplications needed for the fast
Fourier transform of n numbers, writing n = r1 * r2 where r1 is a prime.
- add comment and matching formula, with crossrefs.
Replace:
%F A122811 a(n) = Omega(A038457(n)), where Omega(n) = A001222(n).
%Y A122811 Cf. A001222, A038457, A122376.
with:
%C A122811 This sequence first differs from A059975(n) at n=16, because 3^3.5.7 is less than 3.5.7.11.
%F A122811 a(n) = Omega(A038547(n)), where Omega(n) = A001222(n).
%Y A122811 Cf. A001222, A038547, A122376, A059975.
Add:
%C A059975 a(n) is the least number of prime factors (counted with multiplicity) of any integer with n divisors.
%F A059975 a(n) = min(A001222(x): A000005(x)=n).
%Y A059975 Cf. A001222, A000005.
Arguably, this comment for A059975 might actually be a more natural name
for the sequence.
Hugo
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