login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A068951 Scan the primes, record digit-sum if it is itself prime. 1
2, 3, 5, 7, 2, 5, 11, 5, 7, 11, 7, 13, 11, 17, 2, 5, 5, 11, 13, 7, 13, 11, 17, 11, 13, 17, 19, 7, 11, 13, 7, 11, 17, 11, 13, 5, 7, 11, 7, 13, 11, 17, 13, 19, 19, 5, 13, 7, 11, 17, 11, 13, 17, 19, 17, 13, 19, 17, 23, 7, 13, 11, 13, 17, 13, 17, 17, 13, 19, 13, 19, 17, 23, 17, 11, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..76.

EXAMPLE

a(13)=5 since the 13th prime is 41 and 4+1=5, which is prime.

MAPLE

dig := X->convert((convert(X, base, 10)), `+`); a := n->`if`(isprime(dig(ithprime(n)))=true, dig(ithprime(n)), printf(""));

CROSSREFS

Cf. A046704.

Sequence in context: A007605 A077765 A078400 * A139752 A238191 A004088

Adjacent sequences:  A068948 A068949 A068950 * A068952 A068953 A068954

KEYWORD

easy,nonn,base

AUTHOR

Francois Jooste (phukraut(AT)hotmail.com), Mar 10 2002

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 7 04:20 EDT 2020. Contains 333292 sequences. (Running on oeis4.)