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A316116 Least odd primitive abundant number having its prime signature. 0
945, 1575, 2205, 3465, 5775, 7425, 8085, 12705, 15015, 28215, 47025, 49875, 69825, 78975, 81081, 103455, 131625, 153153, 182325, 189189, 297297, 342225, 351351, 363375, 387345, 392445, 474045, 532875, 570375, 692835, 742203, 793611, 1102725, 1380825, 1468935, 1612875 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Ordering of exponents matters; 1575 and 2205 have unordered prime signatures (2, 2, 1) and (2, 1, 2) respectively.
LINKS
EXAMPLE
1575 = 3^2 * 5^2 * 7 has prime signature (2, 2, 1) and is an odd primitive abundant number (A006038). Since 1575 is the smallest such number, it is in the sequence. - Michael B. Porter, Nov 24 2018
MATHEMATICA
lsig={}; lpab = {}; seq={}; Do[ d=Divisors[n]; If[Total[d] > 2 n && Intersection[ lpab, d] == {}, AppendTo[lpab, n]; sig=FactorInteger[n][[;; , 2]]; If[!MemberQ[ lsig, sig], AppendTo[seq, n]; AppendTo[lsig, sig]]], {n, 3, 1700000, 2}]; seq (* Amiram Eldar, Dec 09 2018 *)
CROSSREFS
Sequence in context: A243104 A006038 A287646 * A188439 A275472 A275066
KEYWORD
nonn
AUTHOR
David A. Corneth, Aug 18 2018
STATUS
approved

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Last modified June 18 04:26 EDT 2024. Contains 373468 sequences. (Running on oeis4.)