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 A014312 Numbers with exactly 4 ones in binary expansion. 16
 15, 23, 27, 29, 30, 39, 43, 45, 46, 51, 53, 54, 57, 58, 60, 71, 75, 77, 78, 83, 85, 86, 89, 90, 92, 99, 101, 102, 105, 106, 108, 113, 114, 116, 120, 135, 139, 141, 142, 147, 149, 150, 153, 154, 156, 163, 165, 166, 169, 170, 172, 177, 178, 180, 184, 195, 197 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS T. D. Noe and Ivan Neretin, Table of n, a(n) for n = 1..10000 [terms 1..1000 from T. D. Noe] FORMULA a(n+1) = A057168(a(n)). - M. F. Hasler, Aug 27 2014 MATHEMATICA Select[ Range[ 180 ], (Count[ IntegerDigits[ #, 2 ], 1 ]==4)& ] (* Olivier Gérard *) PROG (Perl) \$N = 4; my \$vector = 2 ** \$N - 1;  # first key (15) for (1..100) {   print "\$vector, ";   my (\$v, \$d) = (\$vector, 0);   until (\$v & 1 or !\$v) { \$d = (\$d << 1)|1; \$v >>= 1 }   \$vector += \$d + 1 + ((\$v ^ (\$v + 1)) >> 2);  # next key } # Ruud H.G. van Tol, Mar 02 2014 (PARI) for(n=0, 10^3, if(hammingweight(n)==4, print1(n, ", "))); \\ Joerg Arndt, Mar 04 2014 (PARI) print1(t=15); for(i=2, 50, print1(", "t=A057168(t))) \\ M. F. Hasler, Aug 27 2014 CROSSREFS Cf. A090706. Cf. A000079, A018900, A014311, A014312, A014313, A023688, A023689, A023690, A023691 (Hamming weight = 1, 2, ..., 9), A057168. Sequence in context: A219683 A166665 A317295 * A129387 A171167 A242412 Adjacent sequences:  A014309 A014310 A014311 * A014313 A014314 A014315 KEYWORD nonn,base,easy AUTHOR Al Black (gblack(AT)nol.net) EXTENSIONS Extension by Olivier Gérard STATUS approved

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Last modified October 23 01:24 EDT 2018. Contains 316518 sequences. (Running on oeis4.)