A124275 Terms of A123856 that are not terms of A124273.

2, 5, 181

Offset

1,1

Comments

Primes that divide A123855(p-1) = Sum_{j=1..p-1} Sum_{i=1..p-1} prime(i)^j but not A124271(p) = Sum_{i=1..p} (prime(i)^p - 1)/(prime(i) - 1).

The next term if it exists is greater than 1000.

The next term A124275(4), if it exists, is larger than 25000. (Checked by calculating sequences A123856 and A124273 to 1200 terms.) - M. F. Hasler, Nov 10 2006

Links

Table of n, a(n) for n=1..3.

Example

A123856(n) begins {2, 3, 5, 7, 13, 17, 19, 31, 47, 59, 61, 71, 101, 103, 107, 109, 137, 149, 151, 157, 167, 181, 197, ...}.
A124273(n) begins {3, 7, 13, 17, 19, 31, 47, 59, 61, 71, 101, 103, 107, 109, 137, 149, 151, 157, 167, 197, ...}.
Thus a(1) = 2, a(2) = 5, a(3) = 181.

Maple

A124275:=proc(n) option remember; local i1, i2; i1:=1:i2:=1: # find index i1 such that A123856[i1] is > A124275[n-1]; # then continue until A124273 "jumped over" the term A123856[i1] # while n>1 and A123856(i1) <= procname(n-1) or A123856(i1) = A124273(i2) do i1:=i1+1: # find index i2 such that A124273[i2] is >= A123856(i1) # while A124273(i2) < A123856(i1) do i2:=i2+1: od: od: A123856(i1) end; # M. F. Hasler, Nov 10 2006

Crossrefs

Cf. A123855, A123856, A124271, A124273.

Sequence in context: A270585 A041505 A116629 * A013130 A111392 A226071

Adjacent sequences: A124272 A124273 A124274 * A124276 A124277 A124278

Keyword

bref,hard,more,nonn

Author

Alexander Adamchuk, Oct 23 2006

Status

approved