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A339146
a(n) = a(floor(n / 5)) * (n mod 5 + 1); initial terms are 1.
0
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.
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
KEYWORD
nonn
AUTHOR
STATUS
approved