|
| |
|
|
A158328
|
|
Lessers p1 of twin primes with prime sums of digits of p1 and p2.
|
|
1
|
|
|
|
3, 5, 41, 137, 191, 197, 227, 281, 311, 461, 599, 641, 821, 827, 881, 1031, 1091, 1277, 1301, 1451, 1721, 1871, 2027, 2081, 2087, 2111, 2267, 2591, 2711, 2801, 3167, 3251, 3257, 3299, 3527, 3581, 3671, 3851, 4001, 4157, 4241, 4337, 4421, 4481, 4517, 4799
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
Or, numbers n such that n and n+2 are terms in A046704. [Zak Seidov, Feb 02 2010]
|
|
|
LINKS
|
Robert Israel, Table of n, a(n) for n = 1..10000
|
|
|
EXAMPLE
|
a(3)=41 is in the sequence because 41, 41+2=43, 4+1=5 and 4+3=7 are primes.
a(4)=137 is in the sequence because 137, 137+2=139, 1+3+7=11 and 1+3+9=13 are primes.
|
|
|
MAPLE
|
sd:= n -> convert(convert(n, base, 10), `+`):
p:= 1: q:= 2: count:= 0: Res:= NULL:
while count < 100 do
if q = p+2 and isprime(sd(p)) and isprime(sd(q)) then
count:= count+1; Res:= Res, p
fi;
p:= q; q:= nextprime(q);
od:
Res; # Robert Israel, Apr 08 2018
|
|
|
MATHEMATICA
|
sd[n_]:=Plus@@IntegerDigits[n]; Select[Prime[Range[650]], And@@PrimeQ[{#+2, sd[#], sd[#+2]}] &] (* Jayanta Basu, May 25 2013 *)
|
|
|
CROSSREFS
|
Cf. A001359, A046704.
Sequence in context: A145912 A096058 A120265 * A258933 A060433 A216085
Adjacent sequences: A158325 A158326 A158327 * A158329 A158330 A158331
|
|
|
KEYWORD
|
nonn,base
|
|
|
AUTHOR
|
Juri-Stepan Gerasimov, Mar 16 2009
|
|
|
EXTENSIONS
|
Corrected by Juri-Stepan Gerasimov, Mar 24 2009
3299 and 4481 inserted by R. J. Mathar, Mar 27 2009
Example edited by Robert Israel, Apr 08 2018
|
|
|
STATUS
|
approved
|
| |
|
|
