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A317092
Positive integers whose prime multiplicities are weakly decreasing and span an initial interval of positive integers.
5
2, 3, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 19, 20, 21, 22, 23, 26, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 51, 52, 53, 55, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 73, 74, 76, 77, 78, 79, 82, 83, 84, 85, 86, 87, 89, 91, 92
OFFSET
1,1
LINKS
MATHEMATICA
normalQ[m_]:=Union[m]==Range[Max[m]];
Select[Range[2, 100], And[normalQ[FactorInteger[#][[All, 2]]], OrderedQ[Reverse[FactorInteger[#][[All, 2]]]]]&]
PROG
(PARI) is(n) = my (f=factor(n), w=#f~); if (w==0 || f[w, 2]!=1, return (0), for (k=1, w-1, if (f[k, 2]!=f[k+1, 2] && f[k, 2]!=1+f[k+1, 2], return (0)))
; return (1)) \\ Rémy Sigrist, Sep 05 2018
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jul 21 2018
STATUS
approved