A273003 Arrange the base 10 digits of the n-th Fibonacci number in descending order.

0, 1, 1, 2, 3, 5, 8, 31, 21, 43, 55, 98, 441, 332, 773, 610, 987, 9751, 8542, 8411, 7665, 96410, 77111, 87652, 86643, 75520, 933211, 986411, 873111, 954221, 843200, 9664321, 9873210, 8755432, 8877520, 9765422, 95433210, 87754211, 99886310, 98665432

Offset: 0

Author

Alonso del Arte, May 12 2016

Keywords

• nonn
• base
• easy

Comments

Conjecture: the largest Fibonacci number F(n) with its base 10 digits already sorted in descending order is F(16) = 987.

Examples

			a(7) = 31 because F(7) = 13, so the digits in descending order become 31.
a(8) = 21 = F(8), the digits are already in descending order.
		

Crossrefs

Cf. A000045, A004186, A272918, A273046.

Programs

Mathematica

FromDigits[Reverse[Sort[IntegerDigits[#]]]]&/@Fibonacci[Range[0,50]] (* Harvey P. Dale, Sep 16 2016 *)

PARI

a(n)=fromdigits(vecsort(digits(fibonacci(n)),,4)) \\ Charles R Greathouse IV, May 15 2016

Formula

a(n) = A004186(A000045(n)). - Michel Marcus, May 15 2016

Extensions

Corrected and extended by Harvey P. Dale, Sep 16 2016