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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 (list; graph; refs; listen; history; text; internal format)
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

Juri-Stepan 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

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Last modified September 29 11:42 EDT 2020. Contains 337431 sequences. (Running on oeis4.)