A397432 Composites in A161601 whose binary reversal is composite.

35, 39, 69, 75, 87, 95, 111, 133, 135, 141, 147, 155, 159, 171, 175, 183, 187, 207, 215, 259, 261, 265, 267, 279, 285, 287, 291, 299, 301, 303, 309, 315, 319, 327, 333, 335, 339, 343, 351, 363, 371, 375, 391, 399, 411, 423, 447, 519, 525, 527, 529, 531, 5373

Offset

1,1

Links

Table of n, a(n) for n=1..53.

Mathematica

p[f_] := Module[{n = 1, c = 0}, Reap[While[c < f, With[{d = IntegerDigits[n, 2]}, With[{r = Reverse[d]}, If[d =!= r && n < FromDigits[r, 2],
Sow[{n, FromDigits[r, 2]}]; c++]]]; n += 2]][[2, 1]]];
u = Select[p[300], !PrimeQ[#[[1]]] && !PrimeQ[#[[2]]] &];
Map[First, u]
(* Peter J. C. Moses, Jun 24 2026 *)

Crossrefs

Cf. A000040, A002808, A161601, A161603, A397429, A397430, A397431.

Sequence in context: A094523 A249429 A249423 * A219799 A217007 A141741

Adjacent sequences: A397429 A397430 A397431 * A397433 A397435 A397437

Keyword

nonn,base,easy,new

Author

Clark Kimberling, Jun 26 2026

Status

approved