A276162 Square array read by antidiagonals: T(n,k) = Product_{i = 1..k} gcd(n, i).

1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 3, 4, 1, 1, 1, 2, 3, 4, 1, 1, 2, 1, 8, 3, 8, 1, 1, 1, 6, 1, 8, 9, 8, 1, 1, 2, 1, 12, 5, 16, 9, 16, 1, 1, 1, 2, 1, 12, 5, 16, 9, 16, 1, 1, 2, 3, 8, 1, 72, 5, 64, 27, 32, 1, 1, 1, 2, 3, 8, 1, 72, 5, 64, 27, 32, 1, 1, 2, 1, 4

Offset

1,5

Links

Peter Kagey, Table of n, a(n) for n = 1..10000

Mohamed Abobakr, Greatest common divisor sequence

Example

T(6, 3) = gcd(6, 1) * gcd(6, 2) * gcd(6, 3) = 6.

Prog

(PARI) T(n, k)=prod(i=2, k, gcd(n, i))
for(s=1, 15, for(k=1, s-1, print1(T(s-k, k)", "))) \\ Charles R Greathouse IV, Aug 22 2016
(Haskell) a276162T n k = product $ map (gcd n) [1..k]
-- Peter Kagey, Aug 23 2016

Crossrefs

Cf. A051190, A067911, A092287.

Sequence in context: A107435 A196056 A161095 * A118107 A236548 A249949

Adjacent sequences: A276159 A276160 A276161 * A276163 A276164 A276165

Keyword

nonn,tabl

Author

Peter Kagey, Aug 22 2016

Status

approved