A004917 - OEIS

%I #19 Dec 03 2020 07:35:30

%S 0,1,2,3,4,5,6,7,8,9,10,11,2048,2049,2050,2051,2052,2053,2054,2055,

%T 2056,2057,2058,4096,4097,4098,4099,4100,4101,4102,4103,4104,4105,

%U 6144,6145,6146,6147,6148,6149,6150,6151,6152,8192,8193,8194,8195,8196,8197,8198

%N Numbers that are the sum of at most 11 positive 11th powers.

%H Alois P. Heinz, <a href="/A004917/b004917.txt">Table of n, a(n) for n = 1..10000</a>

%p b:= proc(n, i, t) option remember; n=0 or i>0 and t>0

%p       and (b(n, i-1, t) or i^11<=n and b(n-i^11, i, t-1))

%p     end:

%p a:= proc(n) option remember; local k;

%p       for k from 1+ `if`(n=1, -1, a(n-1))

%p       while not b(k, iroot(k, 11), 11) do od; k

%p     end:

%p seq(a(n), n=1..60);  # _Alois P. Heinz_, Sep 16 2016

%t b[n_, i_, t_] := b[n, i, t] = n == 0 || i > 0 && t > 0 && (b[n, i - 1, t] || i^11 <= n && b[n - i^11, i, t - 1]);

%t a[n_] := a[n] = Module[{k}, For[k = 1 + If[n == 1, -1, a[n - 1]], !b[k, k^(1/11) // Floor, 11], k++]; k];

%t Array[a, 60] (* _Jean-François Alcover_, Dec 03 2020, after _Alois P. Heinz_ *)

%Y Cf. A008455 (11th powers).

%Y Column k=11 of A336820.

%K nonn

%O 1,3

%A _N. J. A. Sloane_

%E More terms from _Alois P. Heinz_, Sep 16 2016