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 A273324 Integers n such that n^2 + 3 is the sum of 4 but no fewer nonzero squares. 3

%I

%S 2,5,6,10,11,14,18,21,22,26,27,30,34,37,38,42,43,46,50,53,54,58,59,62,

%T 66,69,70,74,75,78,82,85,86,90,91,94,98,101,102,106,107,110,114,117,

%U 118,122,123,126,130,133,134,138,139,142,146,149,150,154,155,158,162,165,166,170

%N Integers n such that n^2 + 3 is the sum of 4 but no fewer nonzero squares.

%C If n^2 + k is a term of A004215, then the minimum positive value of k is 3, obviously.

%H Antti Karttunen, <a href="/A273324/b273324.txt">Table of n, a(n) for n = 1..10001</a>

%F a(n) = A000196(1+A278491(n)). - _Antti Karttunen_, Nov 26 2016

%e 2 is in the sequence because 2^2 + 3 = 7 is a term of A004215.

%o (PARI) isA004215(n) = {n\4^valuation(n, 4)%8==7}

%o lista(nn) = for(n=1, nn, if(isA004215(n^2+3), print1(n, ", ")));

%Y Cf. A000196, A004215, A117950, A278491, A278536.

%K nonn,easy

%O 1,1

%A _Altug Alkan_, May 20 2016

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Last modified July 26 09:29 EDT 2021. Contains 346294 sequences. (Running on oeis4.)