OFFSET
1,2
COMMENTS
The sequence is not increasing: a(100) < a(99). - Robert Israel, Jun 30 2017
LINKS
Robert Israel, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = Sum_{k=1..n} digsum(k^n), n >= 1.
EXAMPLE
n=1: 1: 1;
n=2: 1,4: 1+4=5;
n=3: 1,8,27: 1+8+9=18;
n=4: 1,16,81,256: 1+7+9+13=30.
MAPLE
ds:= n -> convert(convert(n, base, 10), `+`):
f:= n -> add(ds(k^n), k=1..n):
map(f, [$1..50]); # Robert Israel, Jun 30 2017
MATHEMATICA
a[n_] := Sum[ Total@ IntegerDigits[k^n], {k, n}]; Array[a, 50] (* Giovanni Resta, Jun 07 2017 *)
PROG
(PARI) a(n) = sum(k=1, n, sumdigits(k^n)); \\ Michel Marcus, Jun 06 2017
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Marian Kraus, Jun 02 2017
STATUS
approved