A186077 Index of Fibonacci and tribonacci numbers having the same last digit.

1, 2, 4, 5, 8, 10, 13, 19, 31, 44, 47, 61, 73, 80, 88, 101, 104, 106, 115, 119, 122, 145, 160, 166, 178, 181, 188, 209, 214, 232, 233, 235, 244, 257, 260, 262, 271, 272, 281, 304, 308, 317, 320, 326, 392, 401, 407, 409, 415, 418, 422, 425, 442, 443, 448, 449

Offset

1,2

Comments

Fib[a(n)]=Trib[a(n)] mod 10.

All corresponding values of Fib and Trib (mod 10) are odd.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(10)=44 since Fib(44)=701408733 and Trib(44)=104479306403 both have 3 as last digit.

Mathematica

Module[{nn=450, f, t}, f=Mod[Fibonacci[Range[nn]], 10]; t=Mod[ LinearRecurrence[ {1, 1, 1}, {1, 1, 1}, nn], 10]; Position[Thread[{f, t}], _?(#[[1]] == #[[2]]&), 1, Heads-> False]]//Flatten (* Harvey P. Dale, Aug 09 2020 *)

Crossrefs

Cf. A000045.

Sequence in context: A281898 A036404 A347355 * A358610 A018498 A002048

Adjacent sequences: A186074 A186075 A186076 * A186078 A186079 A186080

Keyword

nonn,base

Author

Carmine Suriano, Feb 11 2011

Status

approved