login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A099068 Numbers n such that n=P(d_1)*P(d_2)*...*P(d_k)+(P(d_1)+P(d_2)+...+P(d_k)) where d_1 d_2 ... d_k is the decimal expansion of n and P(i) is the i-th prime. 2
23, 119, 428, 918, 1637682, 652827658771 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There is no other term up to 15000000.

a(7) > 10^12. [Donovan Johnson, Mar 26 2010]

There are no other terms < 10^44. - Chai Wah Wu, Aug 12 2017

LINKS

Table of n, a(n) for n=1..6.

C. Rivera, Puzzle 279The Prime Puzzles & Problems connection.

EXAMPLE

1637682 is in the sequence because 1637682=

P(1)*P(6)*P(3)*P(7)*P(6)*P(8)*P(2)+(P(1)+P(6)+P(3)+P(7)+P(6)+P(8)+P(2)).

MATHEMATICA

Do[h=IntegerDigits[n]; l=Length[h]; If[ !MemberQ[h, 0]&&n==Product[Prime[h[[k]]], {k, l}]+Sum[Prime[h[[k]]], {k, l}], Print[n]], {n, 15000000}]

CROSSREFS

Cf. A099067, A099069, A097223, A097227.

Sequence in context: A303411 A069756 A293565 * A220408 A044355 A044736

Adjacent sequences:  A099065 A099066 A099067 * A099069 A099070 A099071

KEYWORD

base,more,nonn

AUTHOR

Farideh Firoozbakht, Oct 29 2004

EXTENSIONS

Definition corrected by D. S. McNeil, Mar 14 2009

a(6) from Donovan Johnson, Mar 26 2010

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 May 31 13:01 EDT 2020. Contains 334748 sequences. (Running on oeis4.)