A061863 Numbers that are the product of the squares of some subset of their digits.

0, 1, 25, 36, 784, 1764, 2916, 36864, 46656, 82944, 746496, 777924, 49787136, 329204736, 429981696, 914457600, 3186376704, 3657830400, 3749847696, 3869835264, 7169347584, 14999390784, 19297377225, 22658678784, 149824733184, 166659897600, 247669456896

Offset

1,3

Links

Charlie Neder, Table of n, a(n) for n = 1..248 (Terms < 10^36)

Example

784 = (7.4)^2

Mathematica

Join[{0}, Select[Range[100000], MemberQ[Times@@@(Subsets[IntegerDigits[#], IntegerLength[#] -1]^2), #]&]] (* To generate all of the terms of the sequence shown above, increase the "Range" to 10^11, but the program will run a very long time. *) (* Harvey P. Dale, Nov 25 2011 *)

Crossrefs

Sequence in context: A167363 A035383 A179803 * A079270 A253025 A127022

Adjacent sequences: A061860 A061861 A061862 * A061864 A061865 A061866

Keyword

base,nice,nonn

Author

Erich Friedman, Jun 23 2001

Extensions

More terms from Naohiro Nomoto, Jun 25 2001

a(24)-a(27) from Charlie Neder, Dec 21 2018

Status

approved