login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A105472
Next-to-last digit of n-th Fibonacci number in decimal representation, a(n) = 0 for n <= 6.
3
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
0,9
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)
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 *)
PROG
(PARI) a(n) = (fibonacci(n) % 100)\10; \\ Michel Marcus, Jan 05 2018
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Apr 09 2005
STATUS
approved