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A176803 a(n) = the smallest natural numbers m such that product of antiharmonic mean of the divisors of n and antiharmonic mean of the divisors of m are integers, a(n) = 0 if no such number exists. 0
1, 4, 0, 1, 4, 0, 0, 4, 1, 100, 0, 0, 9, 0, 0, 1, 100, 4, 0, 1, 0, 0, 0, 0, 1, 25, 0, 0, 325, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Antiharmonic mean of the divisors of number n is rational number b(n) = A001157(n) / A000203(n) = A158274(n) / A158275(n). a(n) = 1 for infinitely many n. a(n) = 1 for numbers from A020487: a(A020487(n)) = 1. a(n) = 1 iff A158275(n) = 1. a(n) = 0 for infinitely many n. a(n) = 0 for even A158275(n).

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

For n = 10; b(10) = 65/9, a(n) = 100 because b(100) = 63; 65/9 * 63 = 455 (integer).

CROSSREFS

Sequence in context: A096008 A122873 A221275 * A115715 A115636 A292143

Adjacent sequences:  A176800 A176801 A176802 * A176804 A176805 A176806

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Apr 26 2010

STATUS

approved

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Last modified October 25 14:34 EDT 2021. Contains 348255 sequences. (Running on oeis4.)