A077476 Numbers n such that the digital binary sum of n equals core(n), the squarefree part of n.

1, 4, 16, 18, 64, 72, 256, 288, 405, 486, 726, 847, 1024, 1125, 1152, 1183, 1620, 1734, 1944, 2166, 2646, 2904, 3174, 3388, 4096, 4500, 4608, 4732, 5766, 6480, 6534, 6727, 6936, 7776, 8664, 10584, 11616, 12250, 12696, 13552, 14406, 16384, 16807, 18000

Offset

1,2

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Example

486 = 2*3^5 hence the squarefree part of 486 is 2*3=6 and the binary representation of 486 is 111100110_2 with 6 1's, hence 486 is in the sequence.

Prog

(PARI) is(n)=my(h=hammingweight(n), t=n/h); denominator(t)==1 && issquare(t) && issquarefree(h) \\ Charles R Greathouse IV, Mar 29 2013

Crossrefs

Sequence in context: A243298 A139719 A117102 * A282552 A278315 A373321

Adjacent sequences: A077473 A077474 A077475 * A077477 A077478 A077479

Keyword

base,nonn

Author

Benoit Cloitre, Dec 01 2002

Status

approved