A112662 Cubes of the form semiprime(k) + k-th composite number.

8, 27, 64, 216, 343, 1000, 24389, 27000, 35937, 42875, 46656, 68921, 74088, 97336, 148877, 226981, 373248, 405224, 456533, 551368, 681472, 970299, 1191016, 1771561, 1860867, 2048383, 2352637, 3112136, 3375000, 4019679, 4410944

Offset

1,1

Comments

Corresponding k's: 1, 6, 15, 50, 78, 219, 4803, 5303, 6973, 8261, 8968, 13058, 13972, 18210, 27426, 41167, ..., . - Robert G. Wilson v, Dec 30 2005

The corresponding cube roots: 2, 3, 4, 6, 7, 10, 29, ..., . - Robert G. Wilson v, Dec 30 2005

Links

Table of n, a(n) for n=1..31.

Mathematica

Composite[n_Integer] := FixedPoint[n + PrimePi@# + 1 &, n + PrimePi@n + 1]; fQ[n_] := Plus @@ Last /@ FactorInteger@n == 2; c = 0; t = {}; Do[ If[fQ[n], c++; a = n + Composite[c]; If[ IntegerQ[a^(1/3)], AppendTo[t, a]]], {n, 10^7}] (* Robert G. Wilson v *)

Crossrefs

Sequence in context: A076969 A179163 A050462 * A121652 A112989 A018832

Adjacent sequences: A112659 A112660 A112661 * A112663 A112664 A112665

Keyword

nonn

Author

Giovanni Teofilatto, Dec 29 2005

Extensions

More terms from Robert G. Wilson v, Dec 30 2005

Status

approved