A048796 Palindromic primes formed from decimal expansion of Pi written backwards then forwards.

3, 131, 32397985356295141314159265358979323

Offset: 1

Author

G. L. Honaker, Jr.

Keywords

• base
• nonn
• bref

Comments

The next term 729096599629...1413141...926995690927 has 2971 digits. - Metin Sariyar, Jul 07 2020

Links

• Chris K. Caldwell and G. L. Honaker, Jr., Prime Curios! 729...927 (2971-digits)
• Shyam Sunder Gupta, Mystery of pi, Exploring the Beauty of Fascinating Numbers, Springer (2025) Ch. 19, 473-497.

Crossrefs

Cf. A000796, A007523, A039954.

Programs

Mathematica

l={};Do[a=Floor[Pi*10^n];r=IntegerReverse[a];r2=Floor[r/10];c=FromDigits[Flatten[IntegerDigits/@Join[r2,a]]];
If[PrimeQ[c],AppendTo[l, c]],{n,0,100}];l (* Metin Sariyar, Jul 07 2020 *)