A176309 Integers k such that k and k^3 +- 1 are nonsquarefree numbers.

49, 50, 68, 99, 116, 117, 124, 125, 128, 175, 176, 243, 244, 245, 275, 276, 315, 316, 324, 325, 343, 344, 351, 360, 361, 423, 424, 425, 459, 460, 472, 475, 476, 549, 604, 605, 700, 704, 716, 724, 725, 775, 776, 832, 833, 844, 845, 846, 847, 848, 867, 868

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

49 = 7*7; 49^3 - 1 = 2^4 * 3^2 * 19 * 43; 49^3 + 1 = 2 * 5^2 * 13 * 181.

Mathematica

f[n_]:=SquareFreeQ[n]; lst={}; Do[If[ !f[n^3-1]&&!f[n^3+1]&&!f[n], AppendTo[lst, n]], {n, 2*6!}]; lst

Crossrefs

Cf. A013929, A176308.

Sequence in context: A050709 A371969 A037412 * A080201 A042199 A257443

Adjacent sequences: A176306 A176307 A176308 * A176310 A176311 A176312

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Apr 14 2010

Status

approved