A325230 Numbers of the form p^k * q, p and q prime, p > q, k > 0.

6, 10, 14, 15, 18, 21, 22, 26, 33, 34, 35, 38, 39, 46, 50, 51, 54, 55, 57, 58, 62, 65, 69, 74, 75, 77, 82, 85, 86, 87, 91, 93, 94, 95, 98, 106, 111, 115, 118, 119, 122, 123, 129, 133, 134, 141, 142, 143, 145, 146, 147, 155, 158, 159, 161, 162, 166, 177, 178

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

The sequence of terms together with their prime indices begins:
    6: {1,2}
   10: {1,3}
   14: {1,4}
   15: {2,3}
   18: {1,2,2}
   21: {2,4}
   22: {1,5}
   26: {1,6}
   33: {2,5}
   34: {1,7}
   35: {3,4}
   38: {1,8}
   39: {2,6}
   46: {1,9}
   50: {1,3,3}
   51: {2,7}
   54: {1,2,2,2}
   55: {3,5}
   57: {2,8}
   58: {1,10}

Maple

filter:= proc(n) local F;
   F:= sort(ifactors(n)[2], (a, b)-> a[1]<b[1]);
   nops(F) = 2 and F[1, 2] = 1;
end proc:
select(filter, [$6..200]); # Robert Israel, Apr 14 2019

Mathematica

Select[Range[100], PrimeOmega[#/Power@@FactorInteger[#][[-1]]]==1&]

Prog

(Python)
from sympy import factorint
A325230_list = [n for n, m in ((n, factorint(n)) for n in range(2, 10**6)) if len(m) == 2 and m[min(m)] == 1] # Chai Wah Wu, Apr 16 2019

Crossrefs

Positions of 1's in A325226.

Cf. A056239, A093641, A112798, A174090, A257541, A307517, A325223, A325224, A325225, A325231.

Sequence in context: A230766 A231877 A080364 * A227299 A082092 A069116

Adjacent sequences: A325227 A325228 A325229 * A325231 A325232 A325233

Keyword

nonn

Author

Gus Wiseman, Apr 13 2019

Status

approved