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A129574 Number of odd divisors of n plus the number of odd divisors of n - 1. 2
1, 2, 3, 3, 3, 4, 4, 3, 4, 5, 4, 4, 4, 4, 6, 5, 3, 5, 5, 4, 6, 6, 4, 4, 5, 5, 6, 6, 4, 6, 6, 3, 5, 6, 6, 7, 5, 4, 6, 6, 4, 6, 6, 4, 8, 8, 4, 4, 5, 6, 7, 6, 4, 6, 8, 6, 6, 6, 4, 6, 6, 4, 8, 7, 5, 8, 6, 4, 6, 8, 6, 5, 5, 4, 8, 8, 6, 8, 6, 4, 7, 7, 4, 6, 8, 6, 6, 6, 4, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) = A001227(n) + A001227(n-1). - Andrew Howroyd, Aug 10 2018
EXAMPLE
a(4) = 3 = sum of row 4 of triangle A129573: (1 + 0 + 1 + 1).
PROG
(PARI) a(n)=numdiv(n >> valuation(n, 2)) + if(n > 1, numdiv((n-1) >> valuation(n-1, 2))) \\ Andrew Howroyd, Aug 10 2018
CROSSREFS
Row sums of A129573.
Cf. A001227.
Sequence in context: A326201 A342625 A295569 * A323466 A130193 A084516
KEYWORD
nonn
AUTHOR
Gary W. Adamson, Apr 22 2007
EXTENSIONS
Name changed and terms a(11) and beyond from Andrew Howroyd, Aug 10 2018
STATUS
approved

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Last modified March 19 01:57 EDT 2024. Contains 370952 sequences. (Running on oeis4.)