A124260 a(n) = Sum_{k=1..A124259(n)} n^k.

4, 126, 12, 4, 780, 94036996914, 56, 8, 9, 1111111110, 132, 12, 30940, 8108730, 240, 16, 306, 18, 380, 20, 204204, 11154, 552, 24, 25, 702, 27, 28, 732540, 27930, 992, 32, 1222980, 62556901638174, 1260, 36, 1926220, 2141490, 1560, 40, 2896404

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..1589

Formula

a(A013929(n)) = A013929(n).

Mathematica

a[n_] := Module[{k = 1, s = n}, While[SquareFreeQ[s], k++; s += n^k]; s]; Array[a, 100] (* Amiram Eldar, Dec 26 2020  *)

Prog

(PARI) a(n) = my(k=1, s); while (issquarefree(s=sum(i=1, k, n^i)), k++); s; \\ Michel Marcus, Dec 26 2020

Crossrefs

Cf. A002378, A013929, A027444, A027445, A124259.

Sequence in context: A286017 A068894 A116944 * A253099 A178842 A054053

Adjacent sequences: A124257 A124258 A124259 * A124261 A124262 A124263

Keyword

nonn

Author

Reinhard Zumkeller, Oct 23 2006

Status

approved