A104641 Numbers n such that n^3 has equal number of odd and even digits.

3, 12, 18, 19, 21, 47, 53, 54, 67, 68, 69, 72, 75, 76, 78, 84, 85, 87, 89, 93, 216, 224, 236, 238, 243, 245, 247, 249, 260, 262, 275, 297, 299, 301, 303, 308, 309, 310, 323, 325, 326, 332, 333, 343, 346, 355, 356, 362, 363, 371, 374, 378, 382, 383, 387, 388, 395, 396

Offset: 1

Author

Zak Seidov, Mar 18 2005

Keywords

• easy
• nonn
• base

Links

• G. C. Greubel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A104639, A104640.

Programs

Mathematica

EqedQ[n_]:= Module[{idn3 = IntegerDigits[n^3]}, Count[idn3, ?EvenQ] == Count[idn3, ?OddQ]]; Select[Range[2000], EqedQ] (* G. C. Greubel, Aug 14 2018 *)

PARI

isok(n) = my(d = digits(n^3)); sum(i=1, #d, 1 - (d[i] % 2)) == sum(i=1, #d, d[i] % 2); \\ Michel Marcus, Oct 05 2013