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A071178
Exponent of the largest prime factor of n.
60
0, 1, 1, 2, 1, 1, 1, 3, 2, 1, 1, 1, 1, 1, 1, 4, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 1, 1, 1, 5, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 6, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1
OFFSET
1,4
COMMENTS
a(n) = the multiplicity of the largest part in the partition having Heinz number n. We define the Heinz number of a partition p = [p_1, p_2, ..., p_r] as Product(p_j-th prime, j=1...r) (concept used by Alois P. Heinz in A215366 as an "encoding" of a partition). For example, for the partition [1, 1, 2, 4, 10] we get 2*2*3*7*29 = 2436. Example: a(18) = 2; indeed, the partition having Heinz number 18 = 2*3*3 is [1,2,2]. - Emeric Deutsch, Jun 04 2015
LINKS
FORMULA
a(n) = A124010(n, A001221(n)); A053585(n) = A006530(n)^a(n). - Reinhard Zumkeller, Aug 27 2011
a(n) = A067255(n, A001222(n)). - Reinhard Zumkeller, Jun 11 2013
Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 1 (since the asymptotic density of A070003 is 0). - Amiram Eldar, Oct 02 2024
MAPLE
with(numtheory): with(padic):
a:= n-> `if`(n=1, 0, ordp(n, max(factorset(n)[]))):
seq(a(n), n=1..120); # Alois P. Heinz, Jun 04 2015
MATHEMATICA
a[n_] := FactorInteger[n] // Last // Last; Table[a[n], {n, 1, 120}] (* Jean-François Alcover, Jun 12 2015 *)
PROG
(Haskell)
a071178 = last . a124010_row -- Reinhard Zumkeller, Aug 27 2011
(Python)
from sympy import factorint
def A071178(n): return max(factorint(n).items())[1] if n>1 else 0 # Chai Wah Wu, Oct 10 2023
(PARI) a(n) = if(n == 1, 0, my(e = factor(n)[, 2]); e[#e]); \\ Amiram Eldar, Oct 02 2024
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Jun 10 2002
STATUS
approved