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A355261
a(n) = largest-nth-power(n, 2) * radical(n) = A000188(n) * A007947(n), where largest-nth-power(n, e) is the largest positive integer b such that b^e divides n.
2
1, 2, 3, 4, 5, 6, 7, 4, 9, 10, 11, 12, 13, 14, 15, 8, 17, 18, 19, 20, 21, 22, 23, 12, 25, 26, 9, 28, 29, 30, 31, 8, 33, 34, 35, 36, 37, 38, 39, 20, 41, 42, 43, 44, 45, 46, 47, 24, 49, 50, 51, 52, 53, 18, 55, 28, 57, 58, 59, 60, 61, 62, 63, 16, 65, 66, 67, 68
OFFSET
1,2
LINKS
FORMULA
Multiplicative with a(p^e) = p^(1+floor(e/2)). - Amiram Eldar, Jul 13 2022
Sum_{k=1..n} a(k) ~ c * n^2, where c = (zeta(3)/2) * Product_{p prime} (1 - 2/p^3 + 1/p^4) = 0.447583182004... . - Amiram Eldar, Nov 13 2022
MAPLE
with(NumberTheory): seq(LargestNthPower(n, 2)*Radical(n), n = 1..68);
MATHEMATICA
Array[Apply[Times, #[[All, 1]]]*Apply[Times, #1^Floor[#2/2] & @@ Transpose@ #] &@ FactorInteger[#] &, 68] (* Michael De Vlieger, Jul 12 2022 *)
PROG
(Python)
from math import prod
from sympy import factorint
def A355261(n): return prod(p**((e>>1)+1) for p, e in factorint(n).items()) # Chai Wah Wu, Jul 13 2022
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Peter Luschny, Jul 12 2022
STATUS
approved