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sigma(n) plus the n-th prime gives a cube.
2

%I #7 Nov 01 2021 15:11:51

%S 178,185,268,548,581,2142,9474,17027,17108,66367,71212,155131,230521,

%T 296001,318558,335880,555896,620041,1141190,1158839,1559606,1650646,

%U 2021877,3274046,3655189,3668878,4023383

%N sigma(n) plus the n-th prime gives a cube.

%e sigma(155131)+p(155131)=2248091=131^3.

%t Select[Range[4024000],IntegerQ[Surd[DivisorSigma[1,#]+Prime[#],3]]&] (* _Harvey P. Dale_, Nov 01 2021 *)

%o (PARI) isok(n) = ispower(sigma(n) + prime(n), 3); \\ _Michel Marcus_, Jan 11 2014

%Y Cf. A114082, A114083.

%K nonn

%O 1,1

%A _Giovanni Resta_, Feb 13 2006