0,2

The sum of two consecutive terms of A034175 is always a perfect square.

Rémy Sigrist, Table of n, a(n) for n = 0..10000

a(n)^2 = A034175(n) + A034175(n+1).

For n = 12:

- A034175(12) + A034175(13) = 7 + 9 = 16 = 4^2,

- hence a(12) = 4.

(PARI) p=0; s=0; for (n=1, 77, s+=2^p; for (v=0, oo, if (!bittest(s, v) && issquare(p+v), print1 (sqrtint(p+v) ", "); p=v; break)))

Cf. A034175.

Sequence in context: A070667 A245349 A122416 * A134665 A271832 A063260

Adjacent sequences: A307781 A307782 A307783 * A307785 A307786 A307787

nonn

Rémy Sigrist, Apr 28 2019

approved