This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A092734 Numbers n occurring in binary representation of n*(n+1)/2. 1
 1, 3, 7, 13, 15, 20, 31, 63, 72, 82, 109, 127, 141, 177, 243, 255, 272, 511, 693, 886, 1023, 1056, 1311, 1350, 1480, 2047, 2130, 2378, 3812, 4039, 4095, 4160, 4982, 5422, 5546, 6906, 6933, 7365, 7956, 8191, 9418, 11531, 12465, 13069, 13713 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..100 EXAMPLE n=13->'1101', 13*(13+1)/2=91->'1011011': '..1101.', therefore 13 is a term. MATHEMATICA Select[Range[15000], SequenceCount[IntegerDigits[(#(#+1))/2, 2], IntegerDigits[ #, 2]]>0&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Nov 20 2019 *) CROSSREFS Cf. A007088, A000217. Sequence in context: A310252 A056530 A310253 * A209839 A192854 A002236 Adjacent sequences:  A092731 A092732 A092733 * A092735 A092736 A092737 KEYWORD nonn AUTHOR Reinhard Zumkeller, Apr 12 2004 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 December 14 05:36 EST 2019. Contains 329978 sequences. (Running on oeis4.)