A082521 Least palindromic prime with at least 2n+1 central 0's.

101, 1300031, 140000041, 19000000091, 1300000000031, 140000000000041, 16000000000000061, 7100000000000000017, 340000000000000000043, 35000000000000000000053, 7400000000000000000000047, 940000000000000000000000049, 13000000000000000000000000031

Offset: 0

Author

Lekraj Beedassy, Apr 30 2003

Keywords

• base
• nonn

Comments

Each term has 2n+1 central 0s but it can occur that there are some more 0s adjacent to them. In such cases, successive terms of this sequence are identical. This can be seen in the b-file at n = 20, 40, 54, 66, 80, 97, 146, ... - Jeppe Stig Nielsen, Apr 04 2025

Links

• Jeppe Stig Nielsen, Table of n, a(n) for n = 0..450

Crossrefs

Cf. A002385, A028989, A098045.

Programs

PARI

A082521(n)=forstep(j=10^(n+1),+oo,10^(n+1),my(d=digits(j), p=fromdigits(vector(2*#d-1,k,if(k<#d,d[k],d[2*#d-k])))); ispseudoprime(p)&&return(p)) \\ Jeppe Stig Nielsen, Apr 04 2025

Extensions

More terms from Joshua Zucker, May 11 2006

a(12) from Jeppe Stig Nielsen, Apr 04 2025