OFFSET
1,1
COMMENTS
The subsequence of prime partial sums of emirps begins: 13, xxx, 787, 1489, 2137, 2843, 3232, 6857, 8369, 11923, 15797, 21943, 24103. The subsubsequence of emirp partial sums of emirps begins: 13, 32911 = emirp(736). Note that 787 is a prime when reversed, but not a different prime. The first square in the sequence is 169 and R(169) = 961 is also a square.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
FORMULA
EXAMPLE
a(x) = 13 + 17 + 31 + 37 + 71 + 73 + 79 + 97 + 107 + 113 + 149 + 157 + 167 + 179 + 199 + 311 + 337 + 347 + 359 + 389 + 701 + 709 + 733 + 739 + 743 + 751 + 761 + 769 + 907 + 937 + 941 = 11923, which is prime, and note that R(11923) = 32911 is also prime.
MATHEMATICA
emirpQ[n_]:=Module[{idn=IntegerDigits[n], ridn}, ridn=Reverse[idn]; idn!= ridn && PrimeQ[FromDigits[ridn]]]; Accumulate[Select[Prime[ Range[ 200]], emirpQ]] (* Harvey P. Dale, Oct 25 2011 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, Feb 03 2010
EXTENSIONS
Corrected by Harvey P. Dale, Oct 25 2011
STATUS
approved