A162840 Numbers k such that the cube of the sum of digits of k equals the product of digits of k.

0, 1, 666666, 1377789, 1377798, 1377879, 1377897, 1377978, 1377987, 1378779, 1378797, 1378977, 1379778, 1379787, 1379877, 1387779, 1387797, 1387977, 1389777, 1397778, 1397787, 1397877, 1398777, 1555888, 1558588, 1558858

Offset

0,3

Links

Chai Wah Wu, Table of n, a(n) for n = 0..10000

Formula

{n: A118880(n)=A007954(n)}. - R. J. Mathar, Jul 19 2009

Example

666666 is in the sequence because (1) cubed sum of its digits is (6+6+6+6+6+6)^3 = 46656, (2) the product of its digits is 6*6*6*6*6*6=46656; 46656=46656.

Maple

A007953 := proc(n) add(d, d=convert(n, base, 10)) ; end: A007954 := proc(n) mul(d, d=convert(n, base, 10)) ; end: A118880 := proc(n) (A007953(n))^3; end: for n from 1 to 2000000 do if A118880(n) = A007954(n) then printf("%d, \n", n) ; fi; od: # R. J. Mathar, Jul 19 2009

Mathematica

Select[Range[0, 156*10^4], Total[IntegerDigits[#]]^3==Times@@IntegerDigits[#]&] (* Harvey P. Dale, Jul 07 2022 *)

Crossrefs

Cf. A007954, A118880, A117720, A034710. - R. J. Mathar, Jul 19 2009

Sequence in context: A069373 A270801 A348832 * A233817 A204887 A251503

Adjacent sequences: A162837 A162838 A162839 * A162841 A162842 A162843

Keyword

base,nonn

Author

Boris Hostnik (megpplus(AT)siol.net), Jul 14 2009

Status

approved