A085255 Numbers having at least two representations as a sum of two powerful numbers (A001694).

17, 33, 36, 40, 41, 50, 52, 57, 65, 68, 72, 73, 76, 80, 81, 85, 89, 97, 104, 108, 109, 113, 116, 117, 125, 129, 130, 132, 133, 136, 137, 144, 145, 148, 152, 153, 157, 160, 164, 170, 172, 177, 180, 185, 189, 193, 197, 200, 201, 204, 205, 208, 209, 216, 221

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 = 222}, 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, A085254.

Sequence in context: A029817 A162504 A336235 * A283395 A244752 A138393

Adjacent sequences: A085252 A085253 A085254 * A085256 A085257 A085258

Keyword

nonn

Author

Reinhard Zumkeller, Jun 23 2003

Status

approved