A098220 a(n) = floor(sigma(sigma(p))/p) = floor(sigma(p+1)/p) = floor(A008333(n)/p), where p is the n-th prime number.

2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 2, 2, 3, 1, 2, 1, 2, 2, 1, 2, 2, 1, 2, 3, 1, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 1, 2, 2, 2, 3, 2, 1, 2, 2, 2, 1, 2, 1, 3, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 3, 1, 2, 2, 3, 2, 2, 1, 1, 1, 2, 2, 2, 2

Offset

1,1

Comments

Values of these quotients are expectedly lower than ratios of A051027(n)/n.

Links

Table of n, a(n) for n=1..105.

Example

For n = 7, the seventh prime is 17, so a(7) = floor(sigma(sigma(17))/17) = floor(sigma(18)/17) = floor(39/17) = 2.

Prog

(PARI) a(n) = my(p=prime(n)); sigma(p+1)\p; \\ Michel Marcus, Dec 23 2018

Crossrefs

Cf. A000203, A051027, A008333, A098219, A098221, A098222.

Sequence in context: A359511 A202146 A087010 * A297032 A346953 A235508

Adjacent sequences: A098217 A098218 A098219 * A098221 A098222 A098223

Keyword

nonn

Author

Labos Elemer, Oct 25 2004

Status

approved