A295007 Numbers n such that the largest digit of n^2 is 7.

24, 26, 42, 52, 61, 69, 74, 76, 82, 84, 85, 88, 124, 131, 132, 144, 154, 165, 166, 174, 181, 189, 194, 218, 224, 226, 234, 239, 240, 260, 265, 266, 269, 271, 274, 275, 276, 319, 326, 356, 371, 376, 384, 415, 416, 418, 419, 420, 421, 448, 455, 466, 474, 476, 520, 521, 524, 525, 526, 552

Offset: 1

Author

M. F. Hasler, Nov 12 2017

Keywords

• nonn
• base

Examples

			24 is in this sequence because 24^2 = 576 has 7 as largest digit.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A295017 (the corresponding squares), A277959 .. A277961 (same for digit 2 .. 4), A295005 .. A295009 (same for digit 5 .. 9).

Cf. A000290 (the squares).

Programs

Maple

filter:= proc(n) max(convert(n^2,base,10))=7 end proc:
select(filter, [$1..1000]); # Robert Israel, Feb 19 2019

PARI

select( is_A295007(n)=n&&vecmax(digits(n^2))==7 , [0..999]) \\ The "n&&" avoids an error message for n=0.

Formula

a(n) = sqrt(A295017(n)), where sqrt = A000196 or A000194 or A003059.