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 A023691 Numbers with exactly 9 ones in binary expansion. 17
 511, 767, 895, 959, 991, 1007, 1015, 1019, 1021, 1022, 1279, 1407, 1471, 1503, 1519, 1527, 1531, 1533, 1534, 1663, 1727, 1759, 1775, 1783, 1787, 1789, 1790, 1855, 1887, 1903, 1911, 1915, 1917, 1918, 1951, 1967, 1975 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Ivan Neretin, Table of n, a(n) for n = 1..10000 Robert Baillie, Summing the curious series of Kempner and Irwin, arXiv:0806.4410 [math.CA], 2008-2015. See p. 18 for Mathematica code irwinSums.m. FORMULA a(n+1) = A057168(a(n)). - M. F. Hasler, Aug 27 2014 Sum_{n>=1} 1/a(n) = 1.386348105265697723853732153017686670695581836109569165990080192653647019078... (calculated using Baillie's irwinSums.m, see Links). - Amiram Eldar, Feb 14 2022 MATHEMATICA Select[ Range[ 511, 2048 ], (Count[ IntegerDigits[ #, 2 ], 1 ]==9)& ] PROG (PARI) is_A023691(n)=hammingweight(n)==9 \\ M. F. Hasler, Aug 27 2014 (PARI) print1(t=2^9-1); for(i=2, 50, print1(", "t=A057168(t))) \\ M. F. Hasler, Aug 27 2014 CROSSREFS Cf. A000079, A018900, A014311, A014312, A014313, A023688, A023689, A023690 (Hamming weight = 1, 2, ..., 8), A057168. Sequence in context: A051985 A103206 A277172 * A045118 A043451 A158011 Adjacent sequences: A023688 A023689 A023690 * A023692 A023693 A023694 KEYWORD nonn,base,easy AUTHOR STATUS approved

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Last modified December 1 23:44 EST 2022. Contains 358485 sequences. (Running on oeis4.)