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A085775 Numbers k such that (k / sum of digits of k) and (k+1 / sum of digits of k+1) are both prime. 7

%I #11 Apr 25 2020 08:41:39

%S 152,803,1016,1853,3031,3032,3438,7361,7542,7587,8226,8337,10095,

%T 10278,10307,11354,11646,13116,13117,13881,17153,21434,21906,23412,

%U 26221,28824,30254,31112,32166,34218,35513,38322,40335,41058,44373,45380

%N Numbers k such that (k / sum of digits of k) and (k+1 / sum of digits of k+1) are both prime.

%H Amiram Eldar, <a href="/A085775/b085775.txt">Table of n, a(n) for n = 1..10000</a>

%e 152 is a term since 152/(1+5+2) = 19 and 153/(1+5+3) = 17 are both prime.

%t moranQ[n_] := PrimeQ[n / Plus @@ IntegerDigits[n]]; Select[Range[50000], moranQ[#] && moranQ[#+1] &] (* _Amiram Eldar_, Apr 25 2020 *)

%Y Subsequence of A001101 and A330927.

%K base,nonn

%O 1,1

%A _Jason Earls_, Jul 23 2003

%E Offset corrected by _Amiram Eldar_, Apr 25 2020

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Last modified April 19 19:02 EDT 2024. Contains 371798 sequences. (Running on oeis4.)