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 A162146 a(n) = the smallest positive integer divisible by exactly n distinct primes, where each of these primes has the same number of digits when written in binary. 0
 1, 2, 6, 7429, 215441, 6678671, 9586934839, 584803025179, 1985383050388741, 204494454190040323, 21880906598334314561, 2385018819218440287149, 269507126571683752447837, 34227405074603836560875299 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Each term of this sequence is squarefree. LINKS EXAMPLE For a(2), 6 = 2 (10_b) * 3 (11_b), For a(3), 7429 = 17 (10001_b) * 19 (10011_b) * 23 (10111_b), For a(4), 215441 = 17 (10001_b) * 19 (10011_b) * 23 (10111_b) * 29 (11101_b), etc. - Robert G. Wilson v, Aug 16 2009 MATHEMATICA f[n_] := Block[{k = 1}, While[p = Select[ Table[i, {i, 2^k, 2^(k + 1) - 1}], PrimeQ@# &]; len = Length@p; len < n, k++ ]; Times @@ Take[p, n]]; Table[ f@n, {n, 0, 15}] (* Robert G. Wilson v, Aug 16 2009 *) CROSSREFS Cf. A162145. Sequence in context: A071093 A114045 A116899 * A231545 A055698 A121167 Adjacent sequences:  A162143 A162144 A162145 * A162147 A162148 A162149 KEYWORD base,nonn AUTHOR Leroy Quet, Jun 25 2009 EXTENSIONS More terms from Robert G. Wilson v, Aug 16 2009 STATUS approved

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Last modified June 26 20:19 EDT 2019. Contains 324380 sequences. (Running on oeis4.)