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A091629 Product of digits associated with A091628(n). Essentially the same as A007283. 10
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

Table of n, a(n) for n=1..30.

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

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Last modified March 26 00:51 EDT 2017. Contains 284111 sequences.