login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A091630 Numbers n + product of digits associated with A091628. 5
29, 235, 2247, 22271, 222319, 2222415, 22222607, 222222991, 2222223759, 22222225295, 222222228367, 2222222234511, 22222222246799, 222222222271375, 2222222222320527, 22222222222418831, 222222222222615439 (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 the only pointer prime (A089823) not containing the digit "1".

The monotonically increasing value of successive product of digits (A091629) strongly suggests that in successive n the digit 1 must be present.

LINKS

Table of n, a(n) for n=1..17.

Carlos Rivera's Prime Puzzles and Problems Connection, Puzzle 251, Pointer primes

FORMULA

a(n) = A091628(n) + A091629(n).

EXAMPLE

a(1) = 23 + 6 = 29.

CROSSREFS

Cf. A089823, A091628, A091629, A091631, A091632.

Sequence in context: A093401 A228408 A042636 * A251424 A027112 A142095

Adjacent sequences:  A091627 A091628 A091629 * A091631 A091632 A091633

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 22 05:47 EDT 2019. Contains 327287 sequences. (Running on oeis4.)