The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A271984 Numbers n such that the denominator of the sum of the reciprocals of the exponents in the binary expansion of 2n is not equal to their LCM. That is, A271410(n) != A116417(n). 1
 34, 35, 36, 37, 38, 39, 44, 45, 46, 47, 50, 51, 52, 53, 54, 55, 60, 61, 62, 63, 98, 99, 100, 101, 102, 103, 108, 109, 110, 111, 114, 115, 116, 117, 118, 119, 124, 125, 126, 127, 164, 165, 166, 167, 172, 173, 174, 175, 180, 181, 182, 183, 188, 189, 190, 191 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(2*n) = 1 + a(2*n-1) for all n > 0. LINKS Peter Kagey, Table of n, a(n) for n = 1..10000 EXAMPLE a(1) = 34 because 34*2 = 68 is the first number such that the LCM of the exponents in its binary expansion (2 and 6) is unequal to the denominator of the sum of reciprocals: lcm(2, 6) = 6 != denominator(1/2 + 1/6) = 3. Equivalently, A271410(34) = 6 != A116417(34) = 3. MATHEMATICA Select[Range@ 1000, (LCM @@ # != Denominator[ Total[1/#]]) &@ Flatten@ Position[ Reverse@ IntegerDigits[#, 2], 1] &] (* Giovanni Resta, Apr 18 2016 *) CROSSREFS Cf. A116417, A271410. Sequence in context: A291512 A165855 A318148 * A254756 A203462 A270311 Adjacent sequences:  A271981 A271982 A271983 * A271985 A271986 A271987 KEYWORD nonn,base,easy AUTHOR Peter Kagey, Apr 17 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)