OFFSET
1,2
FORMULA
a(n) = ceiling(10^((n-1)/4))^4. - Charlie Neder, Jun 13 2019
a(n) = A018074(n-1)^4. - Michel Marcus, Jun 13 2019
EXAMPLE
a(1) = 1^4 = 1;
a(2) = 2^4 = 16;
3^4 = 81 so no increase in number of digits;
a(3) = 4^4 = 256.
PROG
(Magma) sol:=[]; for k in [0..20] do if k mod 4 eq 0 then sol[k+1]:=10^k; else sol[k+1]:=(Floor(10^(k/4)) +1)^4; end if; end for; sol; // Marius A. Burtea, Jun 13 2019
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Akshat Kumar Agarwal, Jun 13 2019
EXTENSIONS
a(11)-a(19) from Charlie Neder, Jun 13 2019
STATUS
approved