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 A248928 Interleave (2*n+2)^2 with (2*n+3)^2, both listed n+1 times. 0

%I

%S 4,9,16,16,25,25,36,36,36,49,49,49,64,64,64,64,81,81,81,81,100,100,

%T 100,100,100,121,121,121,121,121,144,144,144,144,144,144,169,169,169,

%U 169,169,169,196,196,196,196,196,196,196,225,225,225,225,225,225,225

%N Interleave (2*n+2)^2 with (2*n+3)^2, both listed n+1 times.

%C Discovered via Janet's sequence A167268: the result of adding to A167268 the smallest increasing sequence (2, 7, 10, 14, 19, 23, 26, 30, 34, 39, 43, 47, ...) as to get a sequence of nondecreasing squares.

%C Even terms: 4, 16, 16, 36, 36, 36, ... = 4*A093995(n+1).

%C Odd terms: (A131507(n) + 2)^2.

%F a(n) = A027434(n+1)^2.

%e Seen as an irregular triangle:

%e 4;

%e 9;

%e 16, 16;

%e 25, 25;

%e 36, 36, 36;

%e 49, 49, 49;

%e 64, 64, 64, 64;

%e 81, 81, 81, 81;

%e ...

%o (PARI) vector(60, n, (sqrtint(4*n-3)+1)^2) \\ after _Charles R Greathouse IV_, _Michel Marcus_, Oct 27 2014

%Y Cf. A000267, A007395, A027434, A093995, A131507, A167268.

%K nonn,tabf

%O 0,1

%A _Paul Curtz_, Oct 17 2014

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Last modified September 17 12:57 EDT 2019. Contains 327131 sequences. (Running on oeis4.)