Search: id:A070026
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%I A070026
%S A070026 2,3,5,7,11,14,16,20,21,23,25,29,30,32,34,38,41,43,47,50,52,56,61,65,
%T A070026 70,74,83,92,101,102,104,106,110,111,113,115,119,120,122,124,128,131,
%U A070026 133,137,140,142,146,151,155,160,164,173,182,191,200,201,203,205,209
%N A070026 Initial, all intermediate and final iterated sums of digits of n are 
               primes.
%C A070026 2999 = A062802(4) is the smallest term of this sequence for which the 
               second iterated sum of digits is not the final sum; i.e. the smallest 
               requiring three summations (2+9+9+9=29, 2+9=11, 1+1=2 and all three 
               sums are prime). (The corresponding statement about the very large 
               A062802(5) is not true because a large number of smaller nonprimes 
               of the same digit length also have the digit sum 2999, the least 
               being 29999..., where 333 9's follow the 2.). A062802, a sequence 
               of primes, is a subsequence of this sequence and of A070027.
%e A070026 47 is here because 4+7=11 and 11 is prime while also 1+1=2 and 2 is prime. 
               39 (in A028835) is not a term: 3+9=12 is not prime - although 1+2=3 
               is prime. 49 (in A028834) is not a term: 4+9=13 is prime but 1+3=4 
               is not prime.
%Y A070026 Cf. A028834 (Initial sum is prime), A028835 (Final sum is prime), A062802, 
               A070027 (Primes from this sequence).
%Y A070026 Sequence in context: A029979 A029981 A029982 this_sequence A036608 A136185 
               A026812
%Y A070026 Adjacent sequences: A070023 A070024 A070025 this_sequence A070027 A070028 
               A070029
%K A070026 base,easy,nonn
%O A070026 0,1
%A A070026 Rick L. Shepherd (rshepherd2(AT)hotmail.com), Apr 13 2002

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