A104224 Sum of the smallest and the largest n-digit primes.

9, 108, 1098, 10982, 109998, 1099986, 10999994, 110000008, 1099999944, 10999999974, 109999999996, 1099999999992, 11000000000010, 110000000000010, 1100000000000020, 10999999999999974, 110000000000000058

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Chris Caldwell The First 10,000 Primes.

Example

The first term is 9 since it is the sum of 2 and 7, the smallest and largest of 1-digit primes.

Prog

(Sage) def A104224(n): return next_prime(10**(n-1))+previous_prime(10**n) # [D. S. McNeil, Feb 03 2011]

Crossrefs

Sequence in context: A374071 A249048 A080505 * A099676 A268839 A214668

Adjacent sequences: A104221 A104222 A104223 * A104225 A104226 A104227

Keyword

nonn,base

Author

Parthasarathy Nambi, Apr 01 2005

Status

approved