This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A091629 Product of digits associated with A091628(n). Essentially the same as A007283. 9
 6, 12, 24, 48, 96, 192, 384, 768, 1536, 3072, 6144, 12288, 24576, 49152, 98304, 196608, 393216, 786432, 1572864, 3145728, 6291456, 12582912, 25165824, 50331648, 100663296, 201326592, 402653184, 805306368, 1610612736, 3221225472 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Sequence arising in Farideh Firoozbakht's solution to Prime Puzzle 251 - 23 is only pointer prime (A089823) not containing digit "1". The monotonic increasing value of successive product of digits strongly suggests that in successive n the digit 1 must be present. LINKS Tanya Khovanova, Recursive Sequences Carlos Rivera's Prime Puzzles and Problems Connection, Puzzle 251, Pointer primes Index entries for linear recurrences with constant coefficients, signature (2). FORMULA a(n) = 2^n*3 = product of digits of A091628(n). a(n) = 6*2^(n-1). a(n)=2*a(n-1), n>1, a(1)=6. G.f.: 6*x/(1-2x). - Philippe Deléham, Nov 23 2008 EXAMPLE a(1) = 2*3 = 6. MATHEMATICA 3*2^Range[1, 60] (* Vladimir Joseph Stephan Orlovsky, Jun 09 2011 *) CROSSREFS Cf. A089823, A091628, A091630, A091631, A091632. Similar to A003945, A007283, A042950, A058764, A087009. Sequence in context: A160728 A229926 A082505 * A089529 A001766 A110959 Adjacent sequences:  A091626 A091627 A091628 * A091630 A091631 A091632 KEYWORD base,easy,nonn AUTHOR Enoch Haga, Jan 24 2004 EXTENSIONS Edited and extended by Ray Chandler, Feb 07 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.