A078936 Smallest divisor of n*(n+1)/2 that is >= sqrt(n*(n+1)/2).

1, 3, 3, 5, 5, 7, 7, 6, 9, 11, 11, 13, 13, 15, 12, 17, 17, 19, 19, 15, 21, 23, 23, 20, 25, 27, 21, 29, 29, 31, 31, 24, 33, 35, 30, 37, 37, 39, 30, 41, 41, 43, 43, 33, 45, 47, 47, 42, 35, 51, 39, 53, 53, 45, 44, 42, 57, 59, 59, 61, 61, 63, 48, 52, 55, 67, 67, 51, 69, 71, 71, 73

Offset

1,2

Comments

Greater side of integral rectangle with area n*(n+1)/2 having minimal semiperimeter;

a(n) = A033677(A000217(n));

a(n) = A078934(n) - A078935(n); a(n)*A078935(n) = A000217(n).

Links

Table of n, a(n) for n=1..72.

Crossrefs

Sequence in context: A069902 A335568 A085779 * A293702 A061794 A088524

Adjacent sequences: A078933 A078934 A078935 * A078937 A078938 A078939

Keyword

nonn

Author

Reinhard Zumkeller, Dec 17 2002

Status

approved