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Revision History for A369939 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

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Numbers whose maximal exponent in their prime factorization is a Fibonacci number.
(history; published version)
#9 by Amiram Eldar at Wed Aug 07 03:07:55 EDT 2024
STATUS

editing

approved

#8 by Amiram Eldar at Wed Aug 07 03:07:52 EDT 2024
COMMENTS

The asymptotic density of this sequence is 1/zeta(4) + Sum_{k>=5} (1/zeta(Fibonacci(k)+1) - 1/zeta(Fibonacci(k)+1)) = 0.94462177878047854647... .

STATUS

approved

editing

#7 by OEIS Server at Tue Feb 06 08:14:38 EST 2024
LINKS

Amiram Eldar, <a href="/A369939/b369939_1.txt">Table of n, a(n) for n = 1..10000</a>

#6 by Michael De Vlieger at Tue Feb 06 08:14:38 EST 2024
STATUS

reviewed

approved

Discussion
Tue Feb 06
08:14
OEIS Server: Installed first b-file as b369939.txt.
#5 by Joerg Arndt at Tue Feb 06 00:57:35 EST 2024
STATUS

proposed

reviewed

#4 by Amiram Eldar at Tue Feb 06 00:54:11 EST 2024
STATUS

editing

proposed

#3 by Amiram Eldar at Tue Feb 06 00:47:29 EST 2024
LINKS

Amiram Eldar, <a href="/A369939/b369939_1.txt">Table of n, a(n) for n = 1..10000</a>

#2 by Amiram Eldar at Tue Feb 06 00:46:57 EST 2024
NAME

allocated for Amiram EldarNumbers whose maximal exponent in their prime factorization is a Fibonacci number.

DATA

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71

OFFSET

1,2

COMMENTS

First differs from its subsequence A115063 at n = 2448. a(2448) = 2592 = 2^5 * 3^4 is not a term of A115063.

First differs from A209061 at n = 62.

Numbers k such that A051903(k) is a Fibonacci number.

The asymptotic density of this sequence is 1/zeta(4) + Sum_{k>=5} (1/zeta(Fibonacci(k)+1) - 1/zeta(Fibonacci(k)+1)) = 0.94462177878047854647... .

MATHEMATICA

fibQ[n_] := Or @@ IntegerQ /@ Sqrt[5*n^2 + {-4, 4}];

Select[Range[100], fibQ[Max[FactorInteger[#][[;; , 2]]]] &]

PROG

(PARI) isfib(n) = issquare(5*n^2 - 4) || issquare(5*n^2 + 4);

is(n) = n == 1 || isfib(vecmax(factor(n)[, 2]));

CROSSREFS

Cf. A000045, A013662, A051903, A209061.

Subsequences: A005117, A062503, A062838, A113850, A115063.

Similar sequences: A368714, A369937, A369938.

KEYWORD

allocated

nonn,easy

AUTHOR

Amiram Eldar, Feb 06 2024

STATUS

approved

editing

#1 by Amiram Eldar at Tue Feb 06 00:15:01 EST 2024
NAME

allocated for Amiram Eldar

KEYWORD

allocated

STATUS

approved