A030097 Numbers k such that k^2 has only even digits.

0, 2, 8, 20, 22, 68, 78, 80, 92, 162, 168, 200, 202, 220, 262, 298, 478, 492, 498, 668, 680, 780, 800, 898, 908, 920, 932, 1422, 1492, 1498, 1620, 1680, 1692, 2000, 2002, 2020, 2022, 2192, 2200, 2202, 2498, 2502, 2578, 2620, 2832, 2878, 2978, 2980, 4502

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base

Comments

A136904 is a subsequence. - Zak Seidov, Dec 03 2012

Links

• Zak Seidov, Table of n, a(n) for n = 1..2000

Crossrefs

Cf. A030098, A136904.

Programs

Mathematica

Select[ Range[ 3000 ], Union[ EvenQ[ IntegerDigits[ #^2 ] ] ] == {True} & ]

PARI

is_A030097(n)=!setminus(Set(Vec(Str(n^2))),Vec("02468"))  \\ M. F. Hasler, Dec 13 2011

Formula

a(n) = sqrt(A030098(n)). - Zak Seidov, Dec 03 2012

Extensions

More terms from Zak Seidov, May 24 2010