By the way, here's the least inverse of A002487, indexed starting at 1: 0 2 4 8 10 32 18 20 34 38 36 44 42 68 72 92 76 74 82 188 84 140 138 152 150 146 154 266 148 164 172 278 274 170 282 314 276 536 324 296 292 578 300 308 364 332 298 566 330 338 552 548 562 1274 340 584 564 614 628