A147548 - cp's OEIS frontend

A147548 a(n) is the largest n-digit number m such that phi(10^n+1)=phi(m), gcd(10^n+1,m)=1 & 10 doesn't divide m and zero if there is no such m.

n	a(n)
1	0
2	0
3	925
4	9991
5	95969
6	995681
7	9595969
8	99820697
9	894463345
10	9992684743
11	97451082703
12	999896409437
13	9935266565443
14	99974409884813
15	999999115863815
16	9999446015088757
17	99942773726308253
18	999999997876532621
19	9220779220779220841
20	99999797970236297071

[0, 0, 925, 9991, 95969, 995681, 9595969, 99820697, 894463345, 9992684743, 97451082703, 999896409437, 9935266565443, 99974409884813, 999999115863815, 9999446015088757, 99942773726308253, 999999997876532621, 9220779220779220841, 99999797970236297071]

cp's OEIS Frontend

A147548 a(n) is the largest n-digit number m such that phi(10^n+1)=phi(m), gcd(10^n+1,m)=1 & 10 doesn't divide m and zero if there is no such m.

Table of values

List of values