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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

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Last modified August 6 10:01 EDT 2020. Contains 336245 sequences. (Running on oeis4.)