A270141 - OEIS

A270141

A270140 intersect A266005.

1, 2, 6, 42, 720, 1806

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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: A116896 A061062 A375528 * A294349 A325782 A374891

Adjacent sequences: A270138 A270139 A270140 * A270142 A270143 A270144

KEYWORD

nonn,more

AUTHOR

José María Grau Ribas, Mar 12 2016

STATUS

approved