The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A082572 a(n) is the least number m such that the arithmetic mean of the distinct primes dividing m equals n. 2
 2, 3, 15, 5, 35, 7, 39, 65, 51, 11, 95, 13, 115, 161, 87, 17, 155, 19, 111, 185, 123, 23, 215, 141, 235, 329, 159, 29, 371, 31, 183, 305, 427, 201, 335, 37, 219, 365, 511, 41, 395, 43, 415, 581, 267, 47, 623, 1501, 291, 485, 303, 53, 515, 321, 327, 545, 339, 59 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS Are there any terms with more than 3 prime factors? a(p) = p if p is prime. - Paolo P. Lava, Feb 22 2016 LINKS Paolo P. Lava, Table of n, a(n) for n = 2..1000 EXAMPLE a(6) = 35 because the prime factors of 35 are {5, 7}, which have mean 6. MAPLE with(numtheory): P:= proc(q) local a, b, i, n; for i from 2 to q do for n from 2 to q do a:=ifactors(n)[2]; b:=add(a[k][1]*a[k][2], k=1..nops(a))/add(a[k][2], k=1..nops(a)); if type(b, integer) then if i=b and mul(a[k][2], k=1..nops(a))=1 then lprint(b, n); break; fi; fi; od; od; end: P(10^9); # Paolo P. Lava, Feb 22 2016 CROSSREFS Cf. A070009, A078177, A200612. Sequence in context: A262462 A180698 A266618 * A075244 A088030 A101047 Adjacent sequences:  A082569 A082570 A082571 * A082573 A082574 A082575 KEYWORD easy,nonn AUTHOR David Wasserman, May 06 2003 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 May 28 14:47 EDT 2020. Contains 334684 sequences. (Running on oeis4.)