A125497 Evil cubes.

0, 27, 125, 216, 343, 729, 1000, 1331, 1728, 2744, 3375, 4913, 5832, 6859, 8000, 9261, 10648, 13824, 19683, 21952, 27000, 29791, 35937, 39304, 46656, 50653, 54872, 59319, 64000, 68921, 74088, 85184, 103823, 110592, 148877, 157464, 166375

Offset

1,2

Links

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

Example

125 is in the sequence because 5^3 = 125 and its representation in base 2 (1111101) has an even number of 1's.

Maple

a:=proc(k) local k2: k2:=convert(k^3, base, 2): if add(k2[j], j=1..nops(k2)) mod 2=0 then k^3 else fi end: seq(a(k), k=1..70); # Emeric Deutsch, Jan 01 2007
isA001969 := proc(n) local b2 ; b2 := convert(n, base, 2) ; if sum(op(i, b2), i=1..nops(b2)) mod 2 = 0 then RETURN(true) ; else RETURN(false) ; fi ; end : for n from 1 to 80 do if isA001969(n^3) then printf("%d, ", n^3) ; fi ; od ; # R. J. Mathar, Jan 07 2007

Mathematica

Select[Range[0, 55]^3, EvenQ @ DigitCount[#, 2][[1]] &] (* Amiram Eldar, Dec 09 2019 *)

Crossrefs

Intersection of A000578 (cubes) and A001969 (evil numbers).

Sequence in context: A145555 A293894 A137800 * A179145 A369118 A118092

Adjacent sequences: A125494 A125495 A125496 * A125498 A125499 A125500

Keyword

base,nonn

Author

Tanya Khovanova, Dec 27 2006

Extensions

More terms from Emeric Deutsch, Jan 01 2007

More terms from R. J. Mathar, Jan 07 2007

a(1) = 0 inserted by Amiram Eldar, Dec 09 2019

Status

approved