A176721 Partial sums of A047076.

2, 30205, 133050536, 1713435083707, 12173043638400828, 151229306063970112979, 1815272942608097141328160, 16183327444272811414262846321, 331634334544577293143126414662454

Offset: 1

Author

Jonathan Vos Post, Apr 25 2010

Keywords

• base
• nonn

Comments

Partial sums of a(n+1) is the smallest palindromic prime containing exactly 2 more digits on each end than the previous term, with a(n) as a central substring. Can this partial sum ever be a palindromic prime?

Examples

			a(8) = 2 + 30203 + 133020331 + 1713302033171 + 12171330203317121 + 151217133020331712151 + 1815121713302033171215181 + 16181512171330203317121518161 = 16183327444272811414262846321 is prime
		

Crossrefs

Cf. A047076, A046485.

Formula

a(n) = SUM[i=1..n] A047076(i).