A295830 Bi-unitary pseudoperfect numbers that equal to the sum of a subset of their aliquot bi-unitary divisors in a single way.

6, 60, 72, 78, 80, 88, 90, 102, 104, 114, 138, 150, 162, 174, 186, 222, 246, 258, 282, 294, 318, 354, 366, 402, 426, 438, 474, 498, 534, 582, 606, 618, 642, 654, 678, 704, 726, 762, 786, 822, 832, 834, 894, 906, 942, 978, 1002, 1014, 1038, 1074, 1086, 1146

Offset

1,1

Comments

The bi-unitary version of A064771.

Links

Table of n, a(n) for n=1..52.

Example

72 is in the sequence since its aliquot bi-unitary divisors are 1, 2, 4, 8, 9, 18, 36 and {1, 8, 9, 18, 36} is the only subset whose sum is 72.

Mathematica

f[n_] := Select[Divisors[n], Function[d, CoprimeQ[d, n/d]]]; bdiv[m_] := Select[Divisors[m], Last@Intersection[f@#, f[m/#]] == 1 &]; a={}; n=0; While[Length[a]<100, n++; d=Most[bdiv[n]]; c = SeriesCoefficient[ Series[ Product[1+x^d[[i]], {i, Length[d]}], {x, 0, n}], n ]; If[c==1; AppendTo[a, n]]]; a

Crossrefs

Cf. A064771, A292985.

Sequence in context: A136927 A335202 A061475 * A335937 A136937 A295829

Adjacent sequences: A295827 A295828 A295829 * A295831 A295832 A295833

Keyword

nonn

Author

Amiram Eldar, Nov 28 2017

Status

approved