A227932 Evil numbers (A001969) which can be written as a product of two odious numbers (A000069).

77, 147, 154, 169, 175, 209, 231, 245, 275, 287, 294, 308, 325, 329, 338, 343, 350, 399, 407, 413, 418, 427, 441, 455, 462, 469, 483, 490, 525, 533, 550, 553, 567, 574, 588, 605, 609, 616, 649, 650, 658, 676, 679, 686, 700, 703, 715, 735, 759, 763, 777, 798

Offset

1,1

Links

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

Example

Evil number 275 = 25*11. Since 25 and 11 are odious, then 275 is in the sequence.

Mathematica

evilQ[n_] := EvenQ[DigitCount[n, 2][[1]]]; odiousQ[n_] := OddQ[DigitCount[n, 2][[1]]]; fQ[n_] := Module[{f, i}, If[PrimeQ[n], False, f = Select[Divisors[n], # > 1 && # <= Sqrt[n] &]; i = 1; While[i <= Length[f] && ! (odiousQ[f[[i]]] && odiousQ[n/f[[i]]]), i++]; i <= Length[f]]]; Select[Range[1000], evilQ[#] && fQ[#] &] (* T. D. Noe, Oct 16 2013 *)

Crossrefs

Cf. A001969, A000069, A230213, A230226.

Sequence in context: A118611 A072431 A046435 * A004964 A118226 A113945

Adjacent sequences: A227929 A227930 A227931 * A227933 A227934 A227935

Keyword

nonn,base

Author

Vladimir Shevelev, Oct 15 2013

Extensions

Extended by T. D. Noe, Oct 16 2013

Status

approved