A330650 Terms of A330606 which are not squares or powers of 2.

1250, 4802, 31250, 57122, 167042, 235298, 260642, 320000, 559682, 941192, 1229312, 1414562, 3001250, 3543122, 3748322, 5120000, 6837602, 8000000, 9653618, 9759362, 14172488, 14623232, 15059072, 15780962, 19531250, 19668992, 24234722, 35701250, 38614472, 40302242

Offset: 1

Author

Amiram Eldar and Robert G. Wilson v, Dec 22 2019

Keywords

• nonn

Links

• Giovanni Resta, Table of n, a(n) for n = 1..655 (terms < 10^13; first 155 terms from Amiram Eldar and Robert G. Wilson v)

Crossrefs

Cf. A330606.

Programs

Magma

[k:k in [1..10000000]|Gcd(k*NumberOfDivisors(k), DivisorSigma(1, k)) eq 1 and (not IsSquare(k)) and (not IsIntegral(Log(2,k)))]; // Marius A. Burtea, Dec 23 2019

Mathematica

fQ[n_] := CoprimeQ[n*DivisorSigma[0, n], DivisorSigma[1, n]] && !IntegerQ@ Sqrt@ n && !IntegerQ@ Log2@ n; Select[Range[10^6], fQ@# &]