A199973 a(n) = the sum of LCQ_B(n, k) for 1 <= k <= n (see definition in comments).

0, 0, 4, 9, 12, 25, 18, 28, 28, 33, 28, 64, 35, 47, 51, 59, 45, 76, 51, 81, 68, 74, 61, 128, 72, 88, 87, 103, 78, 145, 84, 119, 107, 114, 101, 195, 101, 129, 126, 166

Offset

1,3

Comments

Definition of LCQ_B: The least common non-divisor of type B (LCQ_B) of two positive integers a and b (a<=b) is the least positive non-divisor q of numbers a and b such that 1<=q<=b common to a and b; LCQ_B(a, b) = 0 if no such c exists.

LCQ_B(a, b) = 0 or >= 2.

Links

Table of n, a(n) for n=1..40.

Formula

For n = 6, a(6) = 9 because LCQ_B(6, 1) = 4, LCQ_B(6, 2) = 4, LCQ_B(6, 3) = 4, LCQ_B(6, 4) = 5, LCQ_B(6, 5) = 4, LCQ_B(6, 6) = 4. Sum of results is 25.

Crossrefs

Cf.: A196443 (the sum of GCQ_A(n, k) for 1 <= k <= n).

Cf.: A199972 (the sum of GCQ_B(n, k) for 1 <= k <= n).

Cf.: A199971 (the sum of LCQ_A(n, k) for 1 <= k <= n).

Cf.: A199974 (the sum of LCQ_C(n, k) for 1 <= k <= n).

Sequence in context: A197681 A197624 A339594 * A320925 A212875 A069082

Adjacent sequences: A199970 A199971 A199972 * A199974 A199975 A199976

Keyword

nonn

Author

Jaroslav Krizek, Nov 26 2011

Status

approved