The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A254572 Least multiple of n that is abundant or perfect (A023196). 3
 6, 6, 6, 12, 20, 6, 28, 24, 18, 20, 66, 12, 78, 28, 30, 48, 102, 18, 114, 20, 42, 66, 138, 24, 100, 78, 54, 28, 174, 30, 186, 96, 66, 102, 70, 36, 222, 114, 78, 40, 246, 42, 258, 88, 90, 138, 282, 48, 196, 100, 102, 104, 318, 54, 220, 56, 114, 174, 354, 60 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A254571(n) = a(n)/n for the multipliers. Very often a(n) = A064162(n), but the definition of the latter requires strict abundance. LINKS Robert Israel, Table of n, a(n) for n = 1..10000 MAPLE f:= proc(n) local k; uses numtheory; for k from 1 to 4 do if sigma(k*n)>=2*k*n then return k*n fi od: 6*n end proc: map(f, [\$1..100]); # Robert Israel, Feb 10 2019 MATHEMATICA a[n_] := Do[If[DivisorSigma[1, k*n] >= 2*k*n, Return[k*n]], {k, {1, 2, 3, 4, 6}}]; Table[a[n], {n, 1, 100}] (* Jean-François Alcover, Feb 09 2023 *) PROG (PARI) a(n) = forstep(m=n, 6*n, n, if(sigma(m)>=2*m, return(m))) CROSSREFS Cf. A023196, A064162, A254571. Sequence in context: A315828 A315829 A180604 * A360561 A109047 A337814 Adjacent sequences: A254569 A254570 A254571 * A254573 A254574 A254575 KEYWORD nonn AUTHOR Jeppe Stig Nielsen, Feb 01 2015 STATUS approved

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

Last modified March 22 02:41 EDT 2023. Contains 361413 sequences. (Running on oeis4.)