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

1,1

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.

Links

Table of n, a(n) for n=1..22.

Eric Weisstein's World of Mathematics, Tetradic Number.

Formula

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

Example

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

Crossrefs

Cf. A000040, A006072, A068188.

Sequence in context: A030175 A263805 A058949 * A075842 A037535 A065834

Adjacent sequences: A119739 A119740 A119741 * A119743 A119744 A119745

Keyword

base,easy,nonn,less

Author

Jonathan Vos Post, Jun 16 2006

Extensions

Corrected by Jens Kruse Andersen, Apr 27 2010

Status

approved