Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A080355
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A080355 a(1)=1; for n>1, a(n) = a(n-1) + 2^(j-1), where j is position of n-th 1 in A080339. +0
17
1, 3, 7, 23, 87, 1111, 5207, 70743, 332887, 4527191, 272962647, 1346704471, 70066181207, 1169577808983, 5567624320087, 75936368497751, 4579535995868247, 292809912147579991, 1445731416754426967 (list; graph; listen)
OFFSET

1,2

COMMENT

Or, take an initial segment of A080339, stopping at the n-th 1, reverse, and interpret as a binary number. E.g. to get the 4-th term: 11101 -> 10111 = 23, so a(4) = 23.

FORMULA

a(n) = 1 + Sum_{k=1..n-1} 2^(prime(k)-1).

CROSSREFS

Cf. A076793.

Sequence in context: A136508 A099152 A113860 this_sequence A100964 A080077 A096318

Adjacent sequences: A080352 A080353 A080354 this_sequence A080356 A080357 A080358

KEYWORD

nonn,easy

AUTHOR

njas, based on information supplied by Artur Jasinski (grafix(AT)csl.pl), Mar 21 2003

EXTENSIONS

More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Mar 26 2003

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


AT&T Labs Research