A260312 Palindromic beastly primes that begin and end with digit '1'.

16661, 1000000000000066600000000000001, 10000000000000000000000000000000000000000006660000000000000000000000000000000000000000001

Offset: 1

Author

K. D. Bajpai, Jul 22 2015

Keywords

• nonn
• base
• less

Comments

The next term a(4) contains 1017 digits, and is too large to include in data section.

Examples

			a(1) = 16661 is a palindromic prime that contains the beastly number '666' and begins and ends with digit 1.
a(2) = 1000000000000066600000000000001 is palindromic prime that contains the beastly number '666' and begins and ends with digit 1.
		

Links

• Tony Padilla and Brady Haran, The Most Evil Number, Numberphile video (2018)

Crossrefs

Cf. A046720, A051003, A131645, A186086.

Programs

Magma

[k: n in [1..1000] | IsPrime(k) where k is ((1*10^(n + 2) + 666)*10^n + 1 )];

Maple

A260312:= n-> ((1*10^(n + 2) + 666)*10^n + 1 ): select(isprime, [seq((A260312 (n), n=1..100))]);

Mathematica

Select[Table[(1*10^(n + 2) + 666)*10^n + 1, {n, 1000}], PrimeQ]
Select[Table[FromDigits[Join[{1},PadRight[{},n,0],{6,6,6},PadRight[ {},n,0],{1}]],{n,0,50}],PrimeQ] (* Harvey P. Dale, Jul 09 2017 *)

PARI

for(n=1, 500, k=((1*10^(n + 2) + 666)*10^n + 1 ); if(isprime(k), print1(k, ", ")));