A109405 a(2) = 36; for n >= 3, a(n) = 2^a(n-1) mod 10^n.

36, 736, 8736, 48736, 948736, 2948736, 32948736, 432948736, 3432948736, 53432948736, 353432948736, 5353432948736, 75353432948736, 75353432948736, 5075353432948736, 15075353432948736, 615075353432948736

Offset: 2

Author

N. J. A. Sloane, following email from Max Alekseyev, May 06 2007

Keywords

• nonn

Comments

Decimal digits read backwards form A133612.

Related to but different from A064541 and A121319.

Links

• Harvey P. Dale, Table of n, a(n) for n = 2..1000

Crossrefs

Same as A113627 except for the initial term (14). - Max Alekseyev, May 11 2007

Programs

Mathematica

a = 36; For[n = 3, n < 25, n++, a = PowerMod[2, a, 10^n]; Print[a]] (* Stefan Steinerberger, May 25 2007 *)
nxt[{n_,a_}]:={n+1,PowerMod[2,a,10^(n+1)]}; NestList[nxt,{2,36},20][[All,2]] (* Harvey P. Dale, Jan 22 2023 *)

Extensions

More terms from Stefan Steinerberger, May 25 2007