A154520 - OEIS

A154520

The prime(n)-th digit of the concatenated nonprimes.

1, 4, 8, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 7, 8, 9, 9, 9, 9, 0, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 3, 1, 3, 4, 1, 4, 4, 4, 5, 1, 1, 5, 1, 6, 1, 6, 1, 7, 1, 1, 8, 1, 8, 8, 1, 1, 1, 0, 0, 2, 0, 2, 1, 2, 1, 2, 2, 2, 2, 2, 3, 2, 3, 3, 2, 4, 2, 4, 4, 5, 2, 2, 2, 6, 7, 7, 2

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

The concatenated nonprimes A141468 are A129808 with an initial 0.

LINKS

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

FORMULA

a(n) = A129808(prime(n)-1) .

MAPLE

a129808 := [1] : for n from 4 to 400 do if not isprime(n) then a129808 := [op(a129808), op(ListTools[Reverse](convert(n, base, 10))) ] ; fi; od:

for n from 1 do p := ithprime(n) ; printf("%d, ", op(p-1, a129808) ) ; od: # R. J. Mathar, Aug 03 2009