A062371 Numbers the product of whose nonzero digits is a perfect square.

1, 4, 9, 10, 11, 14, 19, 22, 28, 33, 40, 41, 44, 49, 55, 66, 77, 82, 88, 90, 91, 94, 99, 100, 101, 104, 109, 110, 111, 114, 119, 122, 128, 133, 140, 141, 144, 149, 155, 166, 177, 182, 188, 190, 191, 194, 199, 202, 208, 212, 218, 220, 221, 224, 229, 236, 242, 248

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Example

128 is a member as 1*2*8 = 16 is a square. 140 is also a member as 1*4 = 4.

Prog

(PARI) ok(k)={my(d=digits(k)); issquare(prod(i=1, #d, if(d[i], d[i], 1)))} \\ Andrew Howroyd, Sep 17 2024

Crossrefs

Cf. A062372.

Sequence in context: A166498 A266297 A174800 * A046030 A125726 A352323

Adjacent sequences: A062368 A062369 A062370 * A062372 A062373 A062374

Keyword

nonn,base,easy

Author

Amarnath Murthy, Jun 26 2001

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jul 06 2001

Offset changed by Andrew Howroyd, Sep 17 2024

Status

approved