

A154561


Primes of the form sum of digits of n + sum of digits of prime(n).


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

If n=1 and prime=2, then 1+2=3(prime)=a(1). If n=2 and prime=3, then 2+3=5(prime)=a(2). If n=3 and prime=5, then 3+5=8=composite. If n=4 and prime=7, then 4+7=11(prime)=a(3). If n=5 and prime=11, then 5+1+1=7(prime)=a(4), etc.


MAPLE

Contribution from R. J. Mathar, May 05 2010: (Start)
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: (End)


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


STATUS

approved



