A085254 Numbers having a unique representation as sum of two powerful numbers (A001694).

2, 5, 8, 9, 10, 12, 13, 16, 18, 20, 24, 25, 26, 28, 29, 31, 32, 34, 35, 37, 43, 44, 45, 48, 53, 54, 58, 59, 61, 63, 64, 74, 82, 88, 90, 91, 96, 98, 99, 100, 101, 106, 112, 121, 122, 124, 126, 127, 128, 134, 135, 140, 141, 146, 149, 150, 155, 161, 162, 169, 171

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Powerful Number.

Formula

A085252(a(n)) = 1.

Mathematica

With[{m = 180}, pow = Select[Range[m], # == 1 || Min[FactorInteger[#][[;; , 2]]] > 1 &]; Position[BinCounts[Select[Plus @@@ Union[Sort /@ Tuples[pow, {2}]], # <= m &], {1, m, 1}], 1] // Flatten] (* Amiram Eldar, Jan 30 2023 *)

Crossrefs

Cf. A001694, A076871, A085252, A085253, A085255.

Sequence in context: A153129 A076871 A070049 * A274035 A068537 A047620

Adjacent sequences: A085251 A085252 A085253 * A085255 A085256 A085257

Keyword

nonn

Author

Reinhard Zumkeller, Jun 23 2003

Status

approved