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A075544 Primes which are the sum of the digital root of the first n primes for some n. 3
2, 5, 17, 19, 23, 31, 37, 43, 71, 163, 179, 199, 263, 269, 347, 379, 389, 443, 467, 487, 499, 569, 601, 641, 643, 647, 683, 691, 709, 769, 821, 829, 857, 859, 919, 941, 947, 953, 967, 997, 1019, 1021, 1061, 1093, 1123, 1153, 1231, 1249, 1381, 1409, 1459 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

s = 0; Do[s = s + Mod[ Prime[n], 9]; If[ PrimeQ[s], Print[s]], {n, 1, 350} ]

Select[Accumulate[Mod[Prime[Range[1000]], 9]], PrimeQ] (* Harvey P. Dale, May 04 2012 *)

PROG

(PARI) sumdigits2(n)=local(c); while (n>9, c=0; while (n>0, c=c+n%10; n=n-n%10; n=n/10); n=c); n

c=0; forprime (p=2, 1000, c=c+sumdigits2(p); if (isprime(c), print1(c, ", ")))

CROSSREFS

Cf. A010888, A104247.

Sequence in context: A247857 A025553 A343775 * A104247 A215425 A205511

Adjacent sequences:  A075541 A075542 A075543 * A075545 A075546 A075547

KEYWORD

nonn,base

AUTHOR

Jon Perry, Oct 11 2002

EXTENSIONS

Edited by Robert G. Wilson v, Oct 14 2002

Definition corrected by M. F. Hasler, Apr 04 2007

Corrected by Harvey P. Dale, May 04 2012

STATUS

approved

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Last modified September 21 21:32 EDT 2021. Contains 347605 sequences. (Running on oeis4.)