A186078 Index of Fibonacci numbers having last digit greater than corresponding tribonacci number.

3, 11, 14, 16, 17, 21, 25, 26, 27, 29, 32, 33, 34, 35, 38, 39, 42, 43, 48, 49, 50, 52, 56, 57, 58, 63, 64, 65, 66, 70, 71, 74, 76, 78, 81, 83, 84, 87, 89, 91, 92, 94, 95, 96, 97, 98, 103, 107, 109, 110, 112, 118, 123, 125, 126, 127, 131, 132, 134, 136, 137

Offset

1,1

Comments

Fib(a(n)) mod 10 > trib(a(n)) mod 10.

Precisely we have A000045(n) % 10 > A000213(n-1) % 10. - Michel Marcus, Jul 18 2013

Natural density 72/155, slightly higher than the 9/20 that would be expected with random sequences mod 10. - Charles R Greathouse IV, Jul 18 2013

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Formula

a(n) = a(n-864) + 1860. - Charles R Greathouse IV, Jul 18 2013

Example

a(5)=17 since Fib(17)=A000045(17)=1597 and trib(17)=A000213(16)=7473 and 7>3.

Mathematica

nn = 250; Module[{f = Mod[Fibonacci[Range[nn]], 10],  t = Mod[LinearRecurrence[{1, 1, 1}, {1, 1, 1}, nn], 10], ft},  ft = Thread[{f, t}]; Select[Range[nn], ft[[#, 1]] > ft[[#, 2]] &]] (* Harvey P. Dale, Dec 25 2012 *)

Crossrefs

Cf. A000045, A000213, A186077.

Sequence in context: A158790 A176049 A228237 * A224857 A322608 A063963

Adjacent sequences: A186075 A186076 A186077 * A186079 A186080 A186081

Keyword

nonn,base,easy,less

Author

Carmine Suriano, Feb 11 2011

Status

approved