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%I #13 Apr 22 2015 11:21:12
%S 1,2,4,6,10,11,13,15,19,20,22,24,28,29,31,33,37,40,42,46,48,49,51,55,
%T 57,60,64,66,69,73,75,82,84,88,91,93,97,100,101,103,105,109,110,112,
%U 114,118,119,121,123,127,130,132,136,138,139,141,145,147,150,154,156,159
%N Numbers n such that sum of digits of n+1 is a prime.
%F a(n) = A028834(n) - 1.
%p P:=proc(n) local i,k,w; for i from 1 by 1 to n do w:=0; k:=binomial(i+1,i); while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; if isprime(w) then print(i); fi; od; end: P(1000);
%t Select[Range[200], PrimeQ[Total[IntegerDigits[# + 1]]] &]
%K nonn,base,easy
%O 1,2
%A _Paolo P. Lava_ and _Giorgio Balzarotti_, May 31 2007
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