A090924 Least nonzero number having the same number of digits as n which when added to n yields a prime.

1, 1, 2, 1, 2, 1, 4, 3, 2, 13, 12, 11, 10, 15, 14, 13, 12, 11, 10, 11, 10, 15, 14, 13, 12, 11, 10, 13, 12, 11, 10, 11, 10, 13, 12, 11, 10, 15, 14, 13, 12, 11, 10, 15, 14, 13, 12, 11, 10, 11, 10, 15, 14, 13, 12, 11, 10, 13, 12, 11, 10, 11, 10, 15, 14, 13, 12, 11, 10, 13, 12, 11

Offset

1,3

Links

Table of n, a(n) for n=1..72.

Example

a(29) = 12 and not 8 though 29+8 =37 is also a prime.
a(124) = 103 as 103 is the least three digit number such that 124 +103 = 227 is prime.

Mathematica

lnzn[n_]:=Module[{k=10^(IntegerLength[n]-1)}, While[!PrimeQ[n+k], k++]; k]; Array[lnzn, 80] (* Harvey P. Dale, Jun 17 2012 *)

Crossrefs

Sequence in context: A341827 A138567 A103530 * A247074 A160595 A105778

Adjacent sequences: A090921 A090922 A090923 * A090925 A090926 A090927

Keyword

base,easy,nonn

Author

Amarnath Murthy, Dec 21 2003

Extensions

More terms from David Wasserman, Feb 15 2006

Status

approved