A168174 - OEIS

A168174

Emirps (A006567) with emirp number of digits and emirp digital sum.

1000000001159, 1000000002217, 1000000003463, 1000000004161, 1000000005713, 1000000005911, 1000000006037, 1000000006451, 1000000006699, 1000000007333, 1000000009403, 1000000010249, 1000000010447, 1000000010483, 1000000011019

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Last 13-digit examples: 9999999990583, 9999999990853, 9999999995191, 9999999996901, 9999999997919, 9999999998987. First examples of some digit lengths: 10^16 + {79, 1551, 3711, 7711, 9421, 9867}; 10^30 + {2613, 29979, 37857, 41461, 47577}; 10^36 + {9061, 21081, 52351, 71017, 95781}; 10^70 + {691, 19321, 203403, 225201, 231987}; 10^72 + {97167, 158637, 227001, 233679, 265021}. ... and skipping a few other legal lengths... 10^148 + 53967 -- Jack Brennen

LINKS

Table of n, a(n) for n=1..15.

FORMULA

{p: p in A006567 and A055642(p) in A006567 and A007953(p) in A006567}.

EXAMPLE

a(1) = 1000000001159, which is prime, and R(1000000001159) = 951100000000 is prime, and sod(1000000001159) = 17 is prime, and R(17) = 71 is prime.

CROSSREFS

Cf. A000040, A006567, A167992, A007953, A055642, A114018, A167992.

Sequence in context: A017280 A017520 A017652 * A291321 A233479 A368035

Adjacent sequences: A168171 A168172 A168173 * A168175 A168176 A168177

KEYWORD

base,nonn

AUTHOR

Jonathan Vos Post, Nov 19 2009

STATUS

approved