This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A319057 Minimum sum of a strict factorization of n into factors > 1. 7
 0, 2, 3, 4, 5, 5, 7, 6, 9, 7, 11, 7, 13, 9, 8, 10, 17, 9, 19, 9, 10, 13, 23, 9, 25, 15, 12, 11, 29, 10, 31, 12, 14, 19, 12, 11, 37, 21, 16, 11, 41, 12, 43, 15, 14, 25, 47, 12, 49, 15, 20, 17, 53, 14, 16, 13, 22, 31, 59, 12, 61, 33, 16, 14, 18, 16, 67, 21, 26 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) >= A001414(n), with equality iff n is squarefree or four times a squarefree number (i.e., A000188(n) <= 2). - Charlie Neder, Sep 10 2018 LINKS Charlie Neder, Table of n, a(n) for n = 1..1000 EXAMPLE The strict factorizations of 48 are (48), (2*24), (3*16), (4*12), (6*8), (2*3*8), (2*4*6), with sums 48, 26, 19, 16, 14, 13, 12 respectively, so a(48) = 12. MATHEMATICA strfacs[n_]:=If[n<=1, {{}}, Join@@Table[(Prepend[#, d]&)/@Select[strfacs[n/d], Min@@#>d&], {d, Rest[Divisors[n]]}]]; Table[Min[Total/@strfacs[n]], {n, 100}] CROSSREFS Cf. A001055, A007716, A045778, A056239, A162247, A215366, A246868, A318871, A318953, A318954. Sequence in context: A134875 A134889 A303702 * A181894 A265535 A094802 Adjacent sequences:  A319054 A319055 A319056 * A319058 A319059 A319060 KEYWORD nonn AUTHOR Gus Wiseman, Sep 09 2018 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 15 00:30 EST 2019. Contains 329988 sequences. (Running on oeis4.)