A121167 a(1)=1; a(n) = the reversal of (a(n-1) + spd(a(n-1))), where spd(n) is the sum of d^d for d the digits of n (with 0^0 = 1).

1, 2, 6, 26664, 298661, 386985404, 646010808, 218856976, 288157046, 460585223, 736514774, 427530937, 259106618, 767004366, 507197867, 489519319, 2141658661, 3329758512, 3706874373, 2129616273, 8563597152, 3644768698, 9667076604

Offset: 1

Author

Jason Earls, Aug 14 2006

Keywords

• base
• easy
• nonn
• look

Comments

Eventually periodic with period 7978, as a(23895) = a(31873) = 3365361711. - Robert Israel, Oct 13 2024

Links

• Robert Israel, Table of n, a(n) for n = 1..37363

Crossrefs

Cf. A045503 (spd).

Programs

Maple

f(0):= 1: for i from 1 to 9 do f(i):= i^i od:
rev:= proc(n) local L,i;
  L:= convert(n,base,10);
  add(L[-i]*10^(i-1),i=1..nops(L))
end proc:
R:= 1: x:= 1:
for n from 1 to 25 do
  x:= rev(x + convert(map(f, convert(x,base,10)),`+`));
  R:= R,x
od:
R; # Robert Israel, Oct 13 2024

Mathematica

s={1};fn[n_]:=If[n>0,n^n,1]; Do[AppendTo[s,IntegerReverse[Total[fn/@IntegerDigits[s[[-1]]]]+s[[-1]]]],{n,22}];s (* James C. McMahon, Oct 13 2024 *)

Extensions

Name clarified by Robert Israel, Oct 13 2024