A233182 Numbers that are not the product of a prime and a square.

1, 4, 6, 9, 10, 14, 15, 16, 21, 22, 24, 25, 26, 30, 33, 34, 35, 36, 38, 39, 40, 42, 46, 49, 51, 54, 55, 56, 57, 58, 60, 62, 64, 65, 66, 69, 70, 74, 77, 78, 81, 82, 84, 85, 86, 87, 88, 90, 91, 93, 94, 95, 96, 100, 102, 104, 105, 106, 110, 111, 114, 115, 118, 119, 120, 121, 122, 123, 126

Offset

1,2

Comments

Numbers that are not of the form p*q^2, with p prime, q any integer.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Prog

(PARI) is(n)=!isprime(core(n)) \\ Charles R Greathouse IV, Dec 05 2013
(Python)
from math import isqrt
from sympy import primepi
def A233182(n):
    def f(x): return n+sum(primepi(x//y**2) for y in range(1, isqrt(x)+1))
    m, k = n, f(n)
    while m != k: m, k = k, f(k)
    return m # Chai Wah Wu, Jan 30 2025

Crossrefs

Complement of A229125.

Sequence in context: A010428 A189300 A300079 * A028260 A085155 A371555

Adjacent sequences: A233179 A233180 A233181 * A233183 A233184 A233185

Keyword

nonn

Author

Juri-Stepan Gerasimov, Dec 05 2013

Extensions

Terms corrected by Charles R Greathouse IV, Dec 05 2013

Status

approved