A216471 Smallest k such that k*n^4 + 1 is an n-th power.

1, 3, 271, 61535, 50812751, 21358519, 237419801716063, 1135029771535910655, 8972959412935210028959, 91620671606331844031, 1599468651197092802422012477487, 702649782312030280795815963215, 978557919186290794806960014681034796687

Offset: 1

Author

Michel Lagneau, Sep 10 2012

Keywords

• nonn

Examples

			a(3) = 271 because 271*3^4 + 1 = 21952 = 28^3.
		

Crossrefs

Cf. A076943, A193746, A216439.

Programs

Mathematica

a={}; Do[k = 2; While[ !IntegerQ[(k^n - 1)/n^4], k++ ]; AppendTo[a, (k^n-1)/n^4], {n, 1, 20}]; a