A048839 - OEIS

A048839

Numbers k dividing P(k)!, where P(k) is the largest prime factor of k.

2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 20, 21, 22, 23, 26, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 46, 47, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 73, 74, 76, 77, 78, 79, 82, 83, 84, 85, 86, 87, 88, 89, 91, 92, 93, 94

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OFFSET

1,1

COMMENTS

Solutions to Diophantine equation P(k) = K(k), where P(k) is the largest prime which divides k and K(k) is the Kempner function A002034.

REFERENCES

P. Erdős and C. Ashbacher, Thoughts of Pal Erdos on Some Smarandache Notions, Smarandache Notions Journal, Vol. 8, No. 1-2-3, 1997, 220-224.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) ~ n. - Charles R Greathouse IV, Sep 20 2012

MATHEMATICA

Select[Range[2, 100], Divisible[FactorInteger[#][[-1, 1]]!, #] &] (* Amiram Eldar, May 23 2024 *)

PROG

(PARI) is(n)=my(s=factor(n)[, 1]); s[#s]!%n==0 \\ Charles R Greathouse IV, Sep 20 2012

CROSSREFS

Complement is A057109.

Cf. A002034, A102068.

Sequence in context: A247180 A375398 A317091 * A360477 A122144 A064052

Adjacent sequences: A048836 A048837 A048838 * A048840 A048841 A048842

KEYWORD

nonn,easy

AUTHOR

Charles T. Le (charlestle(AT)yahoo.com)

EXTENSIONS

Corrected and extended by Naohiro Nomoto, Jul 14 2001

STATUS

approved