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Revision History for A104212

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A104212

Sum of the digits of n when the sum is prime.
(history; published version)

#10 by Susanna Cuyler at Sun Jan 20 23:16:31 EST 2019

STATUS

proposed

approved

#9 by Michael De Vlieger at Sun Jan 20 22:18:04 EST 2019

STATUS

editing

proposed

#8 by Michael De Vlieger at Sun Jan 20 22:18:02 EST 2019

MATHEMATICA

Select[Array[Total@ IntegerDigits@ # &, 300], PrimeQ] (* Michael De Vlieger, Jan 20 2019 *)

STATUS

proposed

editing

#7 by Robert Israel at Sun Jan 20 21:58:32 EST 2019

STATUS

editing

proposed

#6 by Robert Israel at Sun Jan 20 21:48:32 EST 2019

KEYWORD

easy,nonn,base,changed,look

#5 by Robert Israel at Sun Jan 20 21:45:59 EST 2019

LINKS

Robert Israel, <a href="/A104212/b104212.txt">Table of n, a(n) for n = 1..10000</a>

#4 by Robert Israel at Sun Jan 20 21:41:53 EST 2019

MAPLE

sd:= n -> convert(convert(n, base, 10), `+`):

select(isprime, map(sd, [$1..400])); # Robert Israel, Jan 20 2019

STATUS

approved

editing

#3 by N. J. A. Sloane at Tue Oct 01 17:58:09 EDT 2013

AUTHOR

_Cino Hilliard (hillcino368(AT)gmail.com), _, Mar 13 2005

Discussion

Tue Oct 01

17:58

OEIS Server: https://oeis.org/edit/global/1955

#2 by N. J. A. Sloane at Wed Dec 06 03:00:00 EST 2006

KEYWORD

easy,nonn,base,new

AUTHOR

Cino Hilliard (hillcino368(AT)hotmailgmail.com), Mar 13 2005

#1 by N. J. A. Sloane at Sat Apr 09 03:00:00 EDT 2005

NAME

Sum of the digits of n when the sum is prime.

DATA

2, 3, 5, 7, 2, 3, 5, 7, 2, 3, 5, 7, 11, 3, 5, 7, 11, 5, 7, 11, 13, 5, 7, 11, 13, 7, 11, 13, 7, 11, 13, 11, 13, 17, 11, 13, 17, 2, 3, 5, 7, 2, 3, 5, 7, 11, 3, 5, 7, 11, 5, 7, 11, 13, 5, 7, 11, 13, 7, 11, 13, 7, 11, 13, 11, 13, 17, 11, 13, 17, 11, 13, 17, 19, 2, 3, 5, 7, 11, 3, 5, 7, 11, 5, 7, 11

OFFSET

1,1

PROG

(PARI) sdprime(n) = { local(x, y); for(x=1, n, y=sumdigits(x); if(isprime(y), print1(y", ") ) ) } sumdigits(n) = \ The sum of the digits of n { local(x, j, s=0); x=digits(n); for(j=1, length(x), s+=x[j]; ); return(s) } digits(n) = \ The vector of the digits of n { return(eval(Vec(Str(n)))) }

KEYWORD

easy,nonn,base

AUTHOR

Cino Hilliard (hillcino368(AT)hotmail.com), Mar 13 2005

STATUS

approved