cp's OEIS Frontend

A332761 Exponents m such that the number of nonnegative k <= n, possessing the property that n + n*k - k is a square, is equal to 2^m.

%I A332761 #30 Sep 08 2022 08:46:25
%S A332761 0,1,0,0,1,1,1,1,1,2,1,1,1,2,1,1,2,2,1,1,1,2,2,1,1,3,1,1,1,2,1,2,1,2,
%T A332761 2,1,2,2,1,1,2,3,1,2,1,2,2,1,1,3,1,1,2,2,1,1,2,3,2,1,1,3,1,1,2,2,2,2,
%U A332761 1,2,2,2,1,3,1,1,2,2,2,2,1,3,1,1,1,3,2,1,2,3,1,2,2,2,2,1,2
%N A332761 Exponents m such that the number of nonnegative k <= n, possessing the property that n + n*k - k is a square, is equal to 2^m.
%C A332761 Where records occur gives 0, 1, 9, 25, 121, 841, 9241, ...
%F A332761 a(n+2) is the exponent r if 2^r is equal to the number of squares of the form k + k*n - n, 0 <= k <= n.
%F A332761 a(n) = A072273(n-1). - _Jinyuan Wang_, Feb 25 2020
%e A332761 a(0) = 0 because 0 + 0*0 - 0 = 1 = 1^2 and 1 = 2^0.
%e A332761 a(1) = 1 because 1 + 1*0 - 0 = 1 = 1^2, 1 + 1*1 - 1 = 1^2 and 2 = 2^1.
%e A332761 a(9) = 2 because 9 + 9*0 - 0 = 9 = 3^2, 9 + 9*2 - 2 = 25 = 5^2, 9 + 9*8 - 8 = 64 = 8^2, 9 + 9*9 - 9 = 81 = 9^2 and 4 = 2^2.
%o A332761 (Magma) [[m: m in [0..n] | #[k: k in [0..n] | IsSquare(n+n*k-k)] eq 2^m]: n in [0..100]];
%Y A332761 Cf. A000290, A072273, A060594, A332802.
%K A332761 nonn
%O A332761 0,10
%A A332761 _Juri-Stepan Gerasimov_, Feb 23 2020
%E A332761 a(70) corrected by _Jinyuan Wang_, Feb 25 2020