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

Author

Amarnath Murthy, Jun 26 2001

Keywords

• nonn
• base
• easy

Examples

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

Links

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

Crossrefs

Cf. A062372.

Programs

PARI

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

Extensions

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

Offset changed by Andrew Howroyd, Sep 17 2024