A380117 a(n) = n - A380118(n).

0, 1, 2, 1, 2, 2, 3, 2, 0, 0, 1, 1, 2, 2, 2, 1, 2, 2, 3, 3, 3, 3, 4, 4, 0, 0, -2, -2, -1, -1, 0, -1, -1, -1, -1, -1, 0, 0, 0, 0, 1, 1, 2, 2, 2, 2, 3, 3, -3, -3, -3, -3, -2, -2, -2, -2, -2, -2, -1, -1, 0, 0, 0, -1, -1, -1, 0, 0, 0, 0, 1, 1, 2, 2, 2, 2, 2, 2, 3

Offset

1,3

Comments

Conjecture: The sign of the terms changes infinitely often.

Links

Peter Luschny, Table of n, a(n) for n = 1..20000

Maple

ExpLambda := n -> n / ilcm(op(numtheory[divisors](n) minus {1, n})):
A380118 := proc(n) option remember; ifelse(n = 1, 1,
A380118(n-1) + ExpLambda(n) - ifelse(isprime(n), n, 0)) end:
a := n -> n - A380118(n): seq(a(n), n = 1..79);

Crossrefs

Cf. A380118, A182936.

Sequence in context: A134192 A358344 A309342 * A284044 A126305 A088431

Adjacent sequences: A380114 A380115 A380116 * A380118 A380119 A380120

Keyword

sign

Author

Peter Luschny, Jan 30 2025

Status

approved