A278647 First differences of Hypotenuse numbers A009003.

5, 3, 2, 2, 3, 5, 1, 3, 1, 4, 1, 2, 2, 1, 1, 4, 5, 1, 1, 1, 2, 3, 2, 1, 4, 3, 2, 3, 1, 1, 3, 2, 2, 3, 2, 2, 1, 1, 4, 2, 3, 1, 1, 2, 1, 1, 3, 1, 1, 2, 2, 1, 1, 2, 1, 2, 1, 2, 5, 5, 1, 1, 3, 3, 2, 1, 2, 1, 1, 3, 2, 1, 1, 2, 1, 4, 1, 4, 1, 3, 1, 1, 3, 2, 1, 1, 1, 2, 2, 3, 3, 1, 1, 2, 3, 2, 1, 1, 1, 3

Offset

1,1

Comments

a(n) <= 5, since A009003 contains all multiples of 5. - Robert Israel, Dec 08 2016

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

a(n) = A009003(n+1) - A009003(n).

Maple

L:= select(t -> has(numtheory:-factorset(t) mod 4, 1), [$1..1000]):
L[2..-1]-L[1..-2]; # Robert Israel, Dec 08 2016

Mathematica

Differences@ Select[Range@ 208, Length@ PowersRepresentations[#^2, 2, 2] > 1 &] (* Michael De Vlieger, Nov 25 2016, after Alonso del Arte at A009003 *)

Crossrefs

Cf. A009003.

Sequence in context: A088324 A352153 A052038 * A249802 A249574 A090125

Adjacent sequences: A278644 A278645 A278646 * A278648 A278649 A278650

Keyword

nonn

Author

Zhandos Mambetaliyev, Nov 24 2016

Status

approved