A317331 Indices m for which A058304(m) = 1.

4, 8, 11, 16, 20, 23, 27, 32, 36, 40, 43, 47, 52, 55, 59, 64, 68, 72, 75, 80, 84, 87, 91, 95, 100, 104, 107, 111, 116, 119, 123, 128, 132, 136, 139, 144, 148, 151, 155, 160, 164, 168, 171, 175, 180, 183, 187, 191, 196, 200, 203, 208, 212, 215, 219, 223, 228, 232, 235, 239, 244, 247, 251

Offset: 1

Author

A.H.M. Smeets, Jul 26 2018

Keywords

• nonn

Links

• A.H.M. Smeets, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A014577, A058304, A317332, A317333, A317335, A317336.

Programs

Python

n, f, i, p, q = 1, 1, 0, 0, 1
while i < 100000:
    i, p, q = i+1, p*10, q*10
    if i == f:
        p, n = p+1, n+1
        f = f*n
n, a, j = 0, 0, 0
while p%q > 0:
    a, f, p, q = a+1, p//q, q, p%q
    if f == 1:
        n = n+1
        print(n, a-1)

Formula

a(n) = 4*n + A014577(n-1)-1. - A.H.M. Smeets, Jul 29 2018