

A154561


Primes resulting from (sum of digits of k) + (sum of digits of prime(k)) as k runs through the positive integers.


1



3, 5, 11, 7, 13, 17, 23, 13, 23, 23, 13, 17, 23, 29, 19, 17, 29, 23, 17, 19, 23, 29, 23, 19, 31, 23, 17, 19, 29, 31, 31, 23, 11, 19, 19, 17, 19, 23, 17, 17, 17, 23, 29, 31, 23, 29, 23, 13, 19, 19, 31, 23, 23, 17, 11, 31, 23, 13, 23, 29, 23, 29, 29, 19, 23, 31, 37, 29, 37, 17
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..70.


EXAMPLE

k=1 yields a term: prime(1) = 2 and 1 + 2 = 3 is prime, so a(1)=3;
k=2 yields a term: prime(2) = 3 and 2 + 3 = 5 is prime, so a(2)=5;
k=3 does not yield a term: prime(3) = 5 and 3 + 5 = 8 is composite;
k=4 yields a term: prime(4) = 7 and 4 + 7 = 11 is prime, so a(3)=11;
k=5 yields a term: prime(5) = 11 and 5 + 1 + 1 = 7 is prime, so a(4)=7.


MAPLE

A007953 := proc(n) add(d, d=convert(n, base, 10)) ; end proc:
for n from 1 to 300 do a := A007953(n) +A007953(ithprime(n)) ; if isprime(a) then printf("%d, ", a ) ; end if; end do: # R. J. Mathar, May 05 2010


MATHEMATICA

sod[n_]:=Total[IntegerDigits[n]]; Select[Table[sod[n]+sod[Prime[n]], {n, 300}], PrimeQ] (* Harvey P. Dale, Dec 11 2012 *)


CROSSREFS

Cf. A000040.
Sequence in context: A046228 A132162 A168323 * A073653 A225487 A145398
Adjacent sequences: A154558 A154559 A154560 * A154562 A154563 A154564


KEYWORD

nonn,base


AUTHOR

JuriStepan Gerasimov, Jan 12 2009


EXTENSIONS

Corrected from a(35) onwards by R. J. Mathar, May 05 2010
Name corrected and Example section edited by Jon E. Schoenfield, Feb 11 2019


STATUS

approved



