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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.
3
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
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
KEYWORD
nonn
AUTHOR
Douglas Stones (dssto1(AT)student.monash.edu.au), Aug 22 2006
EXTENSIONS
Edited by Ray Chandler, Aug 23 2006
STATUS
approved