A119742 Partial sum of tetradic primes (A068188).

11, 112, 293, 18474, 1026475, 2207286, 4088167, 5970048, 106081049, 206969050, 315070851, 425181862, 536191973, 647373084, 766191895, 946292976, 1127404157, 1309292338, 1497303219, 1686192100, 11694372101, 21776190102

Offset: 1

Author

Jonathan Vos Post, Jun 16 2006

Keywords

• base
• easy
• nonn
• less

Comments

Tetradic primes are primes that are palindromes and use only the digits 0, 1 and 8, so they read the same backwards and upside down. a(1) = 11, a(3) = 293 and a(21) = 11694372101 are primes.

Examples

			a(21) = 11 + 101 + 181 + 18181 + 1008001 + 1180811 + 1880881 + 1881881 + 100111001 + 100888001 + 108101801 + 110111011 + 111010111 + 111181111 + 118818811 + 180101081 + 181111181 + 181888181 + 188010881 + 188888881 + 10008180001 = 11694372101.
		

Links

• Eric Weisstein's World of Mathematics, Tetradic Number.

Crossrefs

Cf. A000040, A006072, A068188.

Formula

a(n) = SUM[i=1..n] A068188(i). a(n) = SUM[i=1..n] {A006072(k) such that A006072(k) is in A000040}.

Extensions

Corrected by Jens Kruse Andersen, Apr 27 2010