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!)
 A331409 a(1)=1; for n>1, a(n) = a(n-1)+n, divided by its largest prime factor. 1
 1, 1, 2, 2, 1, 1, 4, 4, 1, 1, 4, 8, 3, 1, 8, 8, 5, 1, 4, 8, 1, 1, 8, 16, 1, 9, 12, 8, 1, 1, 16, 16, 7, 1, 12, 16, 1, 3, 6, 2, 1, 1, 4, 16, 1, 1, 16, 32, 27, 7, 2, 18, 1, 5, 12, 4, 1, 1, 12, 24, 5, 1, 32, 32, 1, 1, 4, 24, 3, 1, 24, 32, 15, 1, 4, 16, 3, 27, 2, 2, 1, 1, 12, 32, 9 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Rémy Sigrist, Table of n, a(n) for n = 1..10000 EXAMPLE For n=4, a(4) = 2+4 divided by its largest prime factor = 6/3 = 2. MATHEMATICA f[n_] := n/FactorInteger[n][[-1, 1]]; a[1] = 1; a[n_] := a[n] = f[a[n - 1] + n]; Array[a, 100] (* Amiram Eldar, Jan 16 2020 *) PROG (MAGMA) [n eq 1 select 1 else (Self(n-1)+n) div Max(PrimeDivisors(Self(n-1)+n)): n in [1..85]]; // Marius A. Burtea, Feb 17 2020 (PARI) a(n) = if (n==1, 1, my(x=a(n-1)+n); x/vecmax(factor(x)[, 1])); \\ Michel Marcus, Feb 20 2020 CROSSREFS Cf. A006530 (largest prime factor), A208884. Sequence in context: A201757 A053390 A140643 * A108017 A293208 A247364 Adjacent sequences:  A331406 A331407 A331408 * A331410 A331411 A331412 KEYWORD nonn AUTHOR Ali Sada, Jan 16 2020 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 August 6 10:01 EDT 2020. Contains 336245 sequences. (Running on oeis4.)