A122146 Numbers k such that q(k) = M(k) and 4*q(k) <= k, where q(k) is the largest prime divisor of k and M(k) is the largest prime power divisor of k.

20, 28, 30, 35, 42, 44, 52, 55, 60, 65, 66, 68, 70, 76, 77, 78, 84, 85, 88, 91, 92, 95, 99, 102, 104, 105, 110, 114, 115, 116, 117, 119, 124, 130, 132, 133, 136, 138, 140, 143, 145, 148, 152, 153, 154, 155, 156, 161, 164, 165, 170, 171, 172, 174, 182, 184, 185

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[200], Max[Power @@@ (f = FactorInteger[#])] == f[[-1, 1]] <= #/4 &] (* Amiram Eldar, May 23 2024 *)

Prog

(PARI) isok(k) = {my(f = factor(k), pm = 0); if(k > 1 && 4 * f[#f~, 1] <= k, for(i = 1, #f~, pm = max(pm, f[i, 1]^f[i, 2])); pm == f[#f~, 1], 0); } \\ Amiram Eldar, May 23 2024

Crossrefs

Cf. A006530, A034699, A122144, A122145.

Sequence in context: A069827 A194674 A059617 * A032482 A024411 A269986

Adjacent sequences: A122143 A122144 A122145 * A122147 A122148 A122149

Keyword

nonn

Author

Douglas Stones (dssto1(AT)student.monash.edu.au), Aug 22 2006

Extensions

Edited by Ray Chandler, Aug 23 2006

Status

approved