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!)
A083137 Smallest palindromic number relatively prime to all the previous terms. 3
1, 2, 3, 5, 7, 11, 101, 131, 151, 181, 191, 313, 323, 353, 373, 383, 727, 757, 767, 787, 797, 919, 929, 989, 10001, 10301, 10501, 10601, 11111, 11311, 11411, 12421, 12721, 12821, 13031, 13331, 13831, 13931, 14141, 14341, 14741, 14941, 15151, 15451 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

323 is the first composite entry. Conjecture: sequence is infinite.

LINKS

R. J. Mathar and Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 966 terms from R. J. Mathar)

MAPLE

isA002113 := proc(n)

    if digrev(n) = n then

        true;

    else

        false;

    end if;

end proc:

A083137 := proc(n)

    option remember;

    if n =1 then

        1;

    else

        for p from procname(n-1)+1 do

            if isA002113(p) then

                rpr := true;

                for i from 1 to n-1 do

                    if igcd(procname(i), p) > 1 then

                        rpr := false;

                        break;

                    end if;

                end do:

                if rpr then

                    return p ;

                end if;

            end if;

        end do:

    end if;

end proc: # R. J. Mathar, Aug 23 2014

MATHEMATICA

a[1] = 1; a[n_] := a[n] = For[k = a[n-1]+1, True, k++, If[PalindromeQ[k] && AllTrue[Array[a, n-1], CoprimeQ[#, k]&], Return[k]]]; Array[a, 50] (* Jean-Fran├žois Alcover, Jan 17 2018 *)

CROSSREFS

Cf. A002113, A083136, A083139 (primes in this sequence).

Sequence in context: A182051 A052480 A234912 * A180440 A077652 A002385

Adjacent sequences:  A083134 A083135 A083136 * A083138 A083139 A083140

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Apr 24 2003

EXTENSIONS

Corrected and extended by Reinhard Zumkeller, May 05 2003

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 July 27 18:27 EDT 2021. Contains 346308 sequences. (Running on oeis4.)