A082021 - cp's OEIS frontend

A082021 a(0) = 7; for n > 0, a(n) is the greatest prime factor of PP(PP(a(n-1)))*a(n-1)+2 where PP(n) is an abbreviation for PreviousPrime(n).

n	a(n)
0	7
1	23
2	131
3	47
4	643
5	2459
6	2000807
7	503347241
8	82125909539251
9	9617692012399
10	55555555342491359799151
11	1116817987709786226917069
12	578610396154837
13	66992050984853
14	254497141
15	1660738053545999
16	201525986561
17	25600818891233
18	796725607788661087
19	23547857117470471

[7, 23, 131, 47, 643, 2459, 2000807, 503347241, 82125909539251, 9617692012399, 55555555342491359799151, 1116817987709786226917069, 578610396154837, 66992050984853, 254497141, 1660738053545999, 201525986561, 25600818891233, 796725607788661087, 23547857117470471]

cp's OEIS Frontend

A082021 a(0) = 7; for n > 0, a(n) is the greatest prime factor of PP(PP(a(n-1)))*a(n-1)+2 where PP(n) is an abbreviation for PreviousPrime(n).

Table of values

List of values