A270141 A270140 intersect A266005.

1, 2, 6, 42, 720, 1806

Offset

1,2

Comments

There are no other terms below 10^7.

Links

Table of n, a(n) for n=1..6.

Jose María Grau and A. M. Oller-Marcen, Power sums over commutative and unitary rings , arXiv:1603.05787 [math.NT], 2016.

Mathematica

{1}~Join~Select[Range[2, nn], Function[k, And[Union@ Table[Mod[k + #[[i, 1]]^#[[i, 2]], #[[i, 1]]^(#[[i, 2]] + 1)], {i, Length@ #}] == {0}, Union@ Table[IntegerQ[k/(#[[i, 1]]^#[[i, 2]] - 1)], {i, Length@ #}] === {True}] &@ FactorInteger@ k]] (* Michael De Vlieger, Mar 21 2016, after José María Grau Ribas at A266005 and A270140 *)

Crossrefs

Cf. A270140, A266005, A014117.

Sequence in context: A181737 A116896 A061062 * A294349 A325782 A326343

Adjacent sequences: A270138 A270139 A270140 * A270142 A270143 A270144

Keyword

nonn,more

Author

José María Grau Ribas, Mar 12 2016

Status

approved