[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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