A222231 In the number n, replace all (decimal) digits '2' with '7' and vice versa.

0, 1, 7, 3, 4, 5, 6, 2, 8, 9, 10, 11, 17, 13, 14, 15, 16, 12, 18, 19, 70, 71, 77, 73, 74, 75, 76, 72, 78, 79, 30, 31, 37, 33, 34, 35, 36, 32, 38, 39, 40, 41, 47, 43, 44, 45, 46, 42, 48, 49, 50, 51, 57, 53, 54, 55, 56, 52, 58, 59, 60, 61, 67, 63, 64, 65, 66, 62, 68, 69, 20, 21, 27, 23

Offset

0,3

Comments

The map which is applied to primes in A171036.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Mathematica

a[n_]:= IntegerDigits[n]/.{2->7, 7->2} // FromDigits; Table[a[n], {n, 0, 80}] (* Vincenzo Librandi, Jul 30 2013 *)

Prog

(PARI) A222231(n, d=[0, 1, 7, 3, 4, 5, 6, 2, 8, 9])=sum(i=1, #n=digits(n), d[n[i]+1]*10^(#n-i)) \\ gives correct value for n=0 iff d[1]=0, since digits(0)=[] in PARI (v.2.6)

Crossrefs

Cf. A222210-A222254; A171013-A171016, A175770, A171018-A171057.

Sequence in context: A013664 A154173 A075697 * A011252 A165331 A225442

Adjacent sequences: A222228 A222229 A222230 * A222232 A222233 A222234

Keyword

nonn,base,easy

Author

M. F. Hasler, Feb 12 2013

Status

approved