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

Author

Vladimir Shevelev, Oct 15 2013

Keywords

• nonn
• base

Examples

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

Links

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

Crossrefs

Cf. A001969, A000069, A230213, A230226.

Programs

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 *)

Extensions

Extended by T. D. Noe, Oct 16 2013