A099551 Odd part of n modulo 10. Final digit of A000265(n).

1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 1, 3, 3, 7, 5, 1, 7, 9, 9, 5, 1, 1, 3, 3, 5, 3, 7, 7, 9, 5, 1, 1, 3, 7, 5, 9, 7, 9, 9, 5, 1, 1, 3, 1, 5, 3, 7, 3, 9, 5, 1, 3, 3, 7, 5, 7, 7, 9, 9, 5, 1, 1, 3, 1, 5, 3, 7, 7, 9, 5, 1, 9, 3, 7, 5, 9, 7, 9, 9, 5, 1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 1, 3, 3, 7, 5, 3, 7, 9, 9, 5, 1, 1