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%I #17 Jul 03 2021 10:57:59
%S 4,7,8,17,43,83,167,314,707,836,6833,8167,21886,41833,89437,134164,
%T 947617,987917,3143167,3162083,9272917,24060133,60827617,434738887,
%U 529027313,2641873937,5383305583,14141757313
%N a(n) is the smallest m for which there appears for the first time a prime p which equals odd part of sum of digits of m^2.
%C The corresponding primes are 7, 13, 5, 19, 11, 31,...
%e The sequence of odd parts of sums of digits of n^2 begins 1, 1, 9, 7, 7, 9, 13, 5,... . The first appearances of primes are on places 4, 7, 8,..., so a(1) = 4, a(2) = 7, a(3)= 8, etc.
%t Sort[Map[#[[1]][[2]]&,SplitBy[Sort[Select[Map[{(#/2^IntegerExponent[#,2])&[Total[IntegerDigits[#^2]]],#}&,Range[1000000]],PrimeQ[#[[1]]]&]],First]]] (* _Peter J. C. Moses_, May 09 2013 *)
%Y Cf. A221858, A225017, A225039, A225040, A225093.
%K nonn,base
%O 1,1
%A _Vladimir Shevelev_, May 07 2013