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

2, 5, 6, 10, 11, 14, 18, 21, 22, 26, 27, 30, 34, 37, 38, 42, 43, 46, 50, 53, 54, 58, 59, 62, 66, 69, 70, 74, 75, 78, 82, 85, 86, 90, 91, 94, 98, 101, 102, 106, 107, 110, 114, 117, 118, 122, 123, 126, 130, 133, 134, 138, 139, 142, 146, 149, 150, 154, 155, 158, 162, 165, 166, 170

Offset: 1

Author

Altug Alkan, May 20 2016

Keywords

• nonn
• easy

Comments

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

See also the first differences (A278536) of this sequence.

Examples

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

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10001

Crossrefs

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

Programs

PARI

isA004215(n) = {n\4^valuation(n, 4)%8==7}
lista(nn) = for(n=1, nn, if(isA004215(n^2+3), print1(n, ", ")));

Formula

a(n) = A000196(1+A278491(n)). - Antti Karttunen, Nov 26 2016