A287894 - OEIS

%I #21 Jun 30 2017 20:38:50

%S 1,5,18,30,33,94,136,186,225,268,348,413,502,682,792,938,1098,1254,

%T 1441,1529,1647,1905,2148,2392,2674,2961,3150,3493,3804,4007,4417,

%U 4636,5103,5576,5850,6234,6769,7175,7659,7713,8538,8848,9406,9957,10332,11218,11877

%N Sum of the digit sums of the n-th powers of the first n positive integers.

%C The sequence is not increasing: a(100) < a(99). - _Robert Israel_, Jun 30 2017

%H Robert Israel, <a href="/A287894/b287894.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = Sum_{k=1..n} digsum(k^n), n >= 1.

%e n=1: 1: 1;

%e n=2: 1,4: 1+4=5;

%e n=3: 1,8,27: 1+8+9=18;

%e n=4: 1,16,81,256: 1+7+9+13=30.

%p ds:= n -> convert(convert(n,base,10),`+`):

%p f:= n -> add(ds(k^n),k=1..n):

%p map(f, [$1..50]); # _Robert Israel_, Jun 30 2017

%t a[n_] := Sum[ Total@ IntegerDigits[k^n], {k, n}]; Array[a, 50] (* _Giovanni Resta_, Jun 07 2017 *)

%o (PARI) a(n) = sum(k=1, n, sumdigits(k^n)); \\ _Michel Marcus_, Jun 06 2017

%Y Cf. A007953.

%K nonn,base

%O 1,2

%A _Marian Kraus_, Jun 02 2017