A119847 Positions where A119842 is zero.

6, 10, 14, 15, 21, 22, 24, 26, 30, 33, 34, 35, 38, 39, 40, 42, 46, 51, 54, 55, 56, 57, 58, 60, 62, 65, 66, 69, 70, 74, 77, 78, 82, 84, 85, 86, 87, 88, 90, 91, 93, 94, 95, 96, 102, 104, 105, 106, 110, 111, 114, 115, 118, 119, 122, 123, 126, 129, 130, 132, 133, 134

Offset

1,1

Comments

In addition to the terms of A119899 includes also terms with prime signature p*q*r, e.g. 30 (= 2*3*5). Anything else?

Links

Alois P. Heinz, Table of n, a(n) for n = 1..6677

Mathematica

b[s_, t_] := b[s, t] = If[Length[s] < 1, 1, Sum[If[Mod[PrimeOmega[x], 2] == 1 - t && Length[Select[s, Mod[#, x] == 0 &]] == 1, b[s~Complement~{x}, 1 - t], 0], {x, s}]]; c[n_] := Module[{l, m}, l = Sort[FactorInteger[n], #1[[2]] > #2[[2]] &]; m = Product[Prime[i]^l[[i]][[2]], {i, 1, Length[l]} ]; b[Divisors[m][[2 ;; -2]], Mod[PrimeOmega[m], 2]]]; A119847 = Position[ Table[c[n], {n, 1, 200}], 0] // Flatten (* Jean-François Alcover, Mar 03 2016, after Alois P. Heinz *)

Crossrefs

Complement: A119848. Superset of A119899. Cf. A119850.

Cf. A229153.

Sequence in context: A268376 A067582 A229153 * A279458 A119899 A351295

Adjacent sequences: A119844 A119845 A119846 * A119848 A119849 A119850

Keyword

nonn

Author

Antti Karttunen, Jun 04 2006

Status

approved