A295009 Numbers k such that the largest digit of k^2 is 9.

3, 7, 13, 14, 17, 23, 27, 30, 31, 33, 36, 37, 43, 44, 47, 53, 54, 57, 63, 64, 67, 70, 73, 77, 83, 86, 87, 89, 93, 95, 96, 97, 98, 99, 103, 107, 113, 114, 117, 118, 123, 127, 130, 133, 134, 136, 137, 138, 139, 140, 141, 143, 147, 148, 153, 157, 158, 161, 163, 164, 167, 170, 171

Offset: 1

Author

M. F. Hasler, Nov 12 2017

Keywords

• nonn
• base

Examples

			23 is in this sequence because 23^2 = 529 has 9 as largest digit.
		

Crossrefs

Cf. A295019 (the corresponding squares), A277959 .. A277961 (same for digit 2 .. 4), A295005 .. A295008 (same for digit 5 .. 8).

Cf. A000290 (the squares).

Programs

PARI

select( is_A295009(n)=n&&vecmax(digits(n^2))==9 , [0..999]) \\ The "n&&" avoids an error message for n=0.

Formula

a(n) = sqrt(A295019(n)), where sqrt = A000196 or A000194 or A003059.