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!)
A109304 Numbers n such that string reversal of n is a substring of n-th prime. 3
7, 94, 281, 886, 16638, 60757, 642469, 689301, 784911, 3631421, 7144652, 7967301, 9428958, 17741923, 75060705, 141521639, 1060975242, 3087218304, 32644390236, 43670299761 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(21) > pi(2*10^12). [From Donovan Johnson, May 08 2010]

LINKS

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

EXAMPLE

94th prime, 491, contains 49 = the string reversal of its index;

281st prime, 1823, contains 182 = the string reversal of its index;

7144652nd prime, 125644177, contains 2564417 = the string reversal of its index; etc.

MATHEMATICA

fQ[n_] := StringPosition[ ToString[ Prime[n]], StringReverse[ ToString[n]]] != {}; Do[ If[ fQ[n], Print[n]], {n, 107350907, 2 10^9}] (* Robert G. Wilson v, Jun 28 2005 *)

CROSSREFS

Corresponding primes form A109305.

Sequence in context: A218835 A219417 A220405 * A134113 A071584 A132114

Adjacent sequences: A109301 A109302 A109303 * A109305 A109306 A109307

KEYWORD

base,nonn

AUTHOR

Zak Seidov, Jun 25 2005

EXTENSIONS

a(14)-a(16) from Robert G. Wilson v, Jun 28 2005

a(17)-a(20) from Donovan Johnson, May 08 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 28 14:10 EST 2023. Contains 359895 sequences. (Running on oeis4.)