A068046 Palindromes of length greater than 1 in decimal expansion of Pi (not showing leading 0's).

141, 535, 979, 323, 46264, 626, 33, 383, 88, 939, 3993, 99, 494, 44, 8998, 99, 11, 808, 32823, 282, 66, 44, 55, 505, 22, 535, 848, 11, 111, 11, 11, 55, 555, 55, 6446, 44, 22, 303, 44, 88, 5665, 66, 33, 44, 33, 19091, 909, 66, 454, 66, 33, 393, 141, 27372, 737, 0, 660, 66, 606, 55, 88, 88, 282, 292, 171, 0

Offset: 1

Author

Reinhard Zumkeller, Feb 11 2002

Keywords

• nonn
• look
• base

Comments

The n-th palindrome starts at A068047(n) and has length A068048(n).

Is this sequence well-defined? For example, how do we know that 141... is not the start of the some very long palindrome in Pi? - Sean A. Irvine, Jan 19 2024

Examples

			Pi = 3.141592653589793238462643383279502884197169399375 ...
a(2) = 535, as the second nontrivial palindrome in Pi is '535', starting at A068047(2) = 9 with length A068048(2) = 3.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000796, A068047, A068048.

Programs

Mathematica

pi = RealDigits[ Pi, 10, 600][[1]]; palQ[n_] := n == Reverse[n]; k = 1; lst = {}; While[j = k + 1; k < 600, While[j < 600 - k, If[ palQ[ Take[pi, {k, j}]], p = FromDigits[ Take[ pi, {k, j}]]; AppendTo[ lst, p]; Print[p]]; j++]; k++]; lst (* Robert G. Wilson v, Jun 11 2013 *)