The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A282771 Integers that are one third of their arithmetic derivatives. 0
 0, 64, 432, 2916, 19683, 50000, 337500, 2278125, 13176688, 39062500, 88942644, 263671875, 600362847, 10294287500, 30517578125, 69486440625, 2712892291396, 4564986729776, 8042412109375, 18312022966923, 30813660425988, 207992207875419, 2119447102653125, 3566395882637500 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS All integers of the form p^p*q^q*r^r, with p, q and r primes, are in the sequence. LINKS Table of n, a(n) for n=1..24. FORMULA Solution of the equation n’ = 3*n. EXAMPLE 337500 = 2^2*3^3*5^5, 337500’ = 1012500 and 337500 = 3*1012500. MAPLE with(numtheory): with(combinat): P:=proc(q) local a, k, n, x, y; x:=[]; y:=[]; for n from 1 to q do for k from 1 to 3 do x:=[op(x), ithprime(n)^ithprime(n)]; od; od; a:=choose(x, 3); for k from 1 to nops(a) do y:=[op(y), convert(a[k], `*`)]; od; y:=sort([op(y)]); print(0); for k from 1 to 100 do print(y[k]); od; end: P(10); CROSSREFS Cf. A003415, A072873, A165558. Sequence in context: A306059 A188785 A317237 * A188821 A181210 A092211 Adjacent sequences: A282768 A282769 A282770 * A282772 A282773 A282774 KEYWORD nonn AUTHOR Paolo P. Lava, Mar 02 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 19 12:47 EDT 2024. Contains 372692 sequences. (Running on oeis4.)