A380797 a(n) is the largest number whose fourth power is an n-digit which has the maximum sum of digits (A373914(n)).

1, 3, 5, 8, 16, 26, 56, 88, 118, 308, 518, 974, 1768, 2868, 5396, 8979, 17306, 28871, 55368, 97063, 167622, 289146, 562341, 835718, 1727156, 3154276, 5623116, 9397404, 17728256, 27831542, 53129506, 98665756, 166025442, 315265896, 510466356, 904245732, 1188893858, 2298249374, 5315776056

Offset: 1

Author

Zhining Yang, Feb 03 2025

Keywords

• nonn
• base

Examples

			a(7) = 56 because among all 7-digit fourth powers, 56^4=9834496 is the largest one (another smaller is 47^4=487968) which has the maximum sum of digits, 43 = A373914(7).
		

Crossrefs

Cf. A373914, A380111.

Other powers: A379298, A380052, A380566, A380193.

Programs

C

/* See A373914. */

Mathematica

a[n_]:=Module[{m=Floor[(10^n-1)^(1/4)], max=0},
For[k=m, k>=Ceiling[10^((n-1)/4)], k--, t=Total@IntegerDigits[k^4];
If[t>max, s=k; max=t]]; s];
Table[a[n], {n, 30}]