A105472 Next-to-last digit of n-th Fibonacci number in decimal representation, a(n) = 0 for n <= 6.

0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 5, 8, 4, 3, 7, 1, 8, 9, 8, 8, 6, 4, 1, 5, 6, 2, 9, 1, 1, 2, 4, 6, 0, 7, 8, 6, 5, 1, 6, 8, 5, 4, 9, 3, 3, 7, 0, 7, 7, 4, 2, 7, 9, 7, 7, 4, 1, 6, 7, 4, 2, 6, 8, 4, 2, 6, 8, 5, 4, 9, 3, 2, 6, 9, 5, 5, 0, 5, 6, 2, 8, 0, 9, 9, 8, 8, 7, 5, 3, 8, 2, 0, 2, 3, 6, 0, 7, 7, 4, 2, 7, 0, 7, 7, 5

Offset: 0

Author

Reinhard Zumkeller, Apr 09 2005

Keywords

• nonn
• base

Comments

a(n) = floor(A105471(n)/10) = floor(A000045(n)/10) mod 10;

A105471(n) = a(n)*10 + A003893(n);

the sequence is periodic with period 300; all blocks of 300 successive terms contain 160 even and 140 odd numbers.

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..10000 (first 601 terms from Alex Ermolaev)

Crossrefs

Cf. A000045, A003893, A105471.

Programs

Mathematica

Array[Mod[Floor[Fibonacci[#]/10], 10] &, 105, 0] (* Michael De Vlieger, Jan 04 2018 *)
Join[{0,0,0,0,0,0,0},Table[IntegerDigits[Fibonacci[n]][[-2]],{n,7,120}]] (* Harvey P. Dale, Aug 22 2020 *)

PARI

a(n) = (fibonacci(n) % 100)\10; \\ Michel Marcus, Jan 05 2018