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!)
A321796 Prime p such that the prime before p is a substring of p^3. 0
3, 17, 31, 59, 997, 2837, 57349, 83773, 224813, 861743, 9999991, 61879669, 95895673, 763137931, 1463016067, 1608398527, 6909512173, 38095693807, 94041857089, 4913845865567 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

10^18-11 and 10^31-27 are also terms. - Giovanni Resta, Nov 20 2018

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

Prime before 3 is 2 and it is a substring of 3^3 = 27.

MAPLE

P:=proc(q) local a, n; for n from 2 to q do a:=ithprime(n);

if searchtext(convert(prevprime(a), string), convert(a^3, string))>0

then print(a); fi; od; end: P(10^5);

MATHEMATICA

sub[x_, y_] := StringPosition @@ ToString /@ {x, y} != {}; p = Prime@ Range@ 100000; p[[Select[Range[2, 100000], sub[p[[#]]^3, p[[# - 1]]] &]]] (* Giovanni Resta, Nov 20 2018 *)

Select[Prime[Range[700000]], SequenceCount[IntegerDigits[#^3], IntegerDigits[ NextPrime[ #, -1]]]>0&] (* The program generates the first 11 terms of the sequence; to generate all terms, increase the Range constant to 174344399360 but the program will take an extremely long time to run. *) (* Harvey P. Dale, Mar 27 2020 *)

CROSSREFS

Cf. A052075.

Sequence in context: A031024 A045437 A343413 * A214093 A309744 A115355

Adjacent sequences:  A321793 A321794 A321795 * A321797 A321798 A321799

KEYWORD

nonn,base,more

AUTHOR

Paolo P. Lava, Nov 19 2018

EXTENSIONS

a(10)-a(20) from Giovanni Resta, Nov 20 2018

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 18 11:20 EDT 2021. Contains 347518 sequences. (Running on oeis4.)