A339146 a(n) = a(floor(n / 5)) * (n mod 5 + 1); initial terms are 1.

1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 2, 4, 6, 8, 10, 3, 6, 9, 12, 15, 4, 8, 12, 16, 20, 5, 10, 15, 20, 25, 1, 2, 3, 4, 5, 2, 4, 6, 8, 10, 3, 6, 9, 12, 15, 4, 8, 12, 16, 20, 5, 10, 15, 20, 25, 1, 2, 3, 4, 5, 2, 4, 6, 8, 10, 3, 6, 9, 12, 15, 4, 8, 12, 16, 20, 5, 10, 15, 20, 25

Offset

0,7

Comments

If a(n) is arranged in a table with row lengths 5, then the first column is the transpose of the first row, followed the transpose of the second row, followed by the transpose of the third row, and so on. The remainder of each row (except the first) is an arithmetic progression whose start and step size equals the first entry of the row.

a(n) = O(n).

limsup_n a(n) = +oo.

Links

Table of n, a(n) for n=0..99.

Example

a(10) = a(2) * 1 = 1.
a(13) = a(2) * 4 = 4.

Prog

(Python)
def a(n):
    if n < 5:
        return 1
    q, r = divmod(n, 5)
    return a(q) * (r + 1)
(PARI) a(n) = if (n < 5, 1, a(n\5)*(n % 5 + 1)); \\ Michel Marcus, Nov 26 2020

Crossrefs

Cf. A194459.

Cf. A048896 (with 2 instead of 5, but shifted).

Sequence in context: A322425 A053841 A010884 * A105932 A106652 A338479

Adjacent sequences: A339143 A339144 A339145 * A339147 A339148 A339149

Keyword

nonn

Author

Robert Dougherty-Bliss, Nov 25 2020

Status

approved