[seqfan] Array organizing natural numbers by the number of subsets of their proper divisors that sum to k=0 .. ?
Antti Karttunen
antti.karttunen at gmail.com
Sun May 10 13:35:33 CEST 2015
Dear Seqfans,
Here is a suggestion for an array, where each row k gives all natural
numbers for which A065205(n) = k, for rows k=0..
(Where https://oeis.org/A065205 "Number of subsets of proper divisors
of n that sum to n.")
Hand-grepping from https://oeis.org/A065205/b065205.txt
I constructed the following north-west corner:
1, 2, 3, 4, 5, 7, 8, 9,
6, 20, 28, 78, 88,
12, 18, 42, 56, 66,
30, 40, 54,350,380,
112,162,294,306,
24,342,352,
80,204,234,
36,220,
228,
Neither of its antidiagonal readings seem to be in OEIS.
The top row is https://oeis.org/A136447 (complement of pseudoperfect numbers)
second row https://oeis.org/A064771
third row https://oeis.org/A152615
fourth row https://oeis.org/A152616
(and the fifth row is not yet in OEIS)
the leftmost column is https://oeis.org/A096356
Assuming that each row contains an infinite number of terms (for each
k), would it make sense to submit this one? Any takers?
Best regards,
Antti
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