The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A282519 Refactorable numbers that are the sum of two refactorable numbers in exactly one way. 1
 2, 9, 18, 24, 60, 88, 625, 1089, 2601, 1500625 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Sequence is a result of investigation on the marked region in graph of A172398(A033950(n)) that is in Links section. Also there are other sequences that marked region has. LINKS Altug Alkan, Illustration of A172398(A033950(n)) S. Colton, Refactorable Numbers - A Machine Invention, J. Integer Sequences, Vol. 2, 1999. Joshua Zelinsky, Tau Numbers: A Partial Proof of a Conjecture and Other Results , Journal of Integer Sequences, Vol. 5 (2002), Article 02.2.8 EXAMPLE Refactorable number 1500625 is a term because 1500625 is the sum of two refactorable numbers in exactly one way, that is, 1500625 = 5^4 * 7^4 = 3^2 * 131^2 + 2^7 * 13 * 809. CROSSREFS Cf. A033950, A172398, A280634, A281663. Sequence in context: A126082 A083707 A240651 * A103256 A028881 A294535 Adjacent sequences:  A282516 A282517 A282518 * A282520 A282521 A282522 KEYWORD nonn,more AUTHOR Altug Alkan, Feb 17 2017 EXTENSIONS a(10) from Giovanni Resta, Feb 17 2017 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 13 20:46 EDT 2021. Contains 342941 sequences. (Running on oeis4.)