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 A139104 Numbers whose binary representation shows the distribution of prime numbers up to the n-th prime, using "0" for primes and "1" for nonprime numbers. 10
 2, 4, 18, 74, 1198, 4794, 76718, 306874, 4909998, 314239934, 1256959738, 80445423294, 1287126772718, 5148507090874, 82376113453998, 5272071261055934, 337412560707579838, 1349650242830319354, 86377615541140438718, 1382041848658247019502, 5528167394632988078010 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) is the decimal representation of A139103(n) interpreted as binary number. LINKS Harvey P. Dale, Table of n, a(n) for n = 1..467 FORMULA a(n) = 2 * A139102(n). From Ridouane Oudra, Aug 27 2019: (Start) a(n) = 2^prime(n) - 1 - (1/2)*(n + Sum_{i=1..prime(n)} 2^(prime(n)-i)*pi(i)), where prime(n) = A000040(n) and pi(n) = A000720(n) a(n) = A001348(n) - A121240(n) a(n) = A118255(A000040(n)). (End) EXAMPLE a(4)=74 because 74 written in base 2 is 1001010 and the string "1001010" shows the distribution of prime numbers up to the 4th prime, using "0" for primes and "1" for nonprime numbers. MATHEMATICA Table[ sum = 0; For[i = 1, i <= Prime[n] , i++, sum = sum*2; If[! PrimeQ[i], sum++]]; sum, {n, 1, 21}] (* Robert Price, Apr 03 2019 *) Module[{nn=30, t}, t=Table[If[PrimeQ[n], 0, 1], {n, Prime[nn]}]; Table[ FromDigits[ Take[t, p], 2], {p, Prime[Range[nn]]}]] (* Harvey P. Dale, Jul 15 2019 *) PROG (PARI) a(n) = fromdigits(vector(prime(n), k, !isprime(k)), 2); \\ Michel Marcus, Apr 04 2019 CROSSREFS Subset of A118255. Cf. A000040, A018252, A139101, A139102, A139103, A139119, A139120, A139122, A000720, A001348, A121240. Sequence in context: A226011 A325850 A052689 * A014448 A277033 A295767 Adjacent sequences:  A139101 A139102 A139103 * A139105 A139106 A139107 KEYWORD nonn AUTHOR Omar E. Pol, Apr 08 2008 EXTENSIONS More terms from R. J. Mathar, May 22 2008 a(19)-a(21) from Robert Price, Apr 03 2019 STATUS approved

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Last modified April 5 00:43 EDT 2020. Contains 333238 sequences. (Running on oeis4.)