A083136 a(n+1) is the smallest palindrome greater than a(n) and relatively prime to a(n).

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 202, 313, 323, 333, 343, 353, 363, 373, 383, 393, 404, 515, 606, 727, 737, 747, 757, 767, 777, 787, 797, 808, 919, 929, 939, 949, 959, 969, 979, 989, 999, 1001, 10001, 10101, 10201

Offset: 1

Author

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

Keywords

• base
• easy
• nonn

Comments

Subsequence of A002113. - Michel Marcus, May 25 2014

Contains at most one 2k-digit number for every k, since all such palindromes are divisible by 11. - Ivan Neretin, Aug 12 2015

Links

• Giovanni Resta, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002113, A081939.

Programs

Mathematica

spal[n_]:=Module[{k=n+1},While[!PalindromeQ[k]||!CoprimeQ[k,n],k++];k]; NestList[spal,1,60] (* Harvey P. Dale, May 09 2021 *)

PARI

ispal(n) = my(d=digits(n)); d == Vecrev(d);
lista(nn) = {print1(last = 1, ", "); for (n=2, nn, if (ispal(n) && gcd(n, last)== 1, print1(n, ", "); last = n;););} \\ Michel Marcus, Aug 12 2015

Extensions

More terms from David Wasserman, Oct 19 2004