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

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A153185 Numbers n such that Q(n) + Q(n^2) + Q(n^3) is a perfect square where Q(n) is the sum of the digits of n. 0
 9, 18, 45, 90, 171, 180, 207, 279, 297, 396, 414, 450, 459, 486, 567, 576, 693, 702, 729, 738, 747, 900, 918, 954, 981, 1062, 1134, 1161, 1197, 1206, 1215, 1233, 1323, 1332, 1341, 1431, 1449, 1467, 1485, 1494, 1503, 1656, 1710, 1737, 1755, 1800, 1908, 2007 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Pedro Henrique O. Pantoja, Problem 3506, Crux Mathematicorum, February 2010, Volume 36 Number 1, p. 45. EXAMPLE 747 is a member: Q(747) = 7+4+7 = 18, Q(747^2) = Q(558009) = 5+5+8+0+0+9 = 27, Q(747^3) = Q(416832723) = 4+1+6+8+3+2+7+2+3 = 36, Q(747) + Q(747^2) + Q(747^3) = 18 + 27 + 36 = 81 = 9^2. MAPLE isA153185 := proc(n) A007953(n)+A007953(n^2)+A007953(n^3) ; issqr(%) ; end proc: for n from 1 to 2200 do if isA153185(n) then printf("%d, ", n); end if; end do: # R. J. Mathar, Jul 08 2010 MATHEMATICA sdnQ[n_]:=IntegerQ[Sqrt[Total[IntegerDigits[n]]+Total[IntegerDigits[ n^2]]+ Total[IntegerDigits[n^3]]]]; Select[Range[2100], sdnQ] (* Harvey P. Dale, Nov 25 2011 *) CROSSREFS Sequence in context: A138900 A202187 A057373 * A325450 A212345 A086500 Adjacent sequences:  A153182 A153183 A153184 * A153186 A153187 A153188 KEYWORD easy,nonn,base AUTHOR Neven Juric (neven.juric(AT)apis-it.hr), Jul 07 2010, corrected Jul 09 2010 EXTENSIONS 1161 inserted by R. J. Mathar, Jul 08 2010 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 January 16 17:26 EST 2021. Contains 340206 sequences. (Running on oeis4.)