login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A165691 Primes p such that pi(p) is the product of the first digit of p and the rest of the number. 0
17, 73, 619, 2077121, 5070613, 503890508623 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A subsequence of A112013. There is no further term up to 3*10^10.

a(7) > 2.07*10^12. - Giovanni Resta, Feb 27 2013

a(7) > 10^17. - Chai Wah Wu, Apr 15 2021

LINKS

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

EXAMPLE

619=prime(6*19), so 619 is in the sequence.

MATHEMATICA

Do[If[h=IntegerDigits[Prime[m]]; m==h[[1]]*FromDigits[Delete[h, 1]],

Print[Prime[m]}]], {m, 355000}]

CROSSREFS

Cf. A000040, A112013.

Sequence in context: A146658 A145440 A112013 * A154419 A208399 A097223

Adjacent sequences:  A165688 A165689 A165690 * A165692 A165693 A165694

KEYWORD

hard,more,nonn,base

AUTHOR

Farideh Firoozbakht, Oct 14 2009

EXTENSIONS

a(6) from Giovanni Resta, Feb 27 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 18 22:29 EDT 2022. Contains 356215 sequences. (Running on oeis4.)