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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

Andrew Howroyd, Table of n, a(n) for n = 1..1000

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

Adjacent sequences:  A129571 A129572 A129573 * A129575 A129576 A129577

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 May 25 14:51 EDT 2022. Contains 354071 sequences. (Running on oeis4.)