A171551 Numbers n with property that decimal expansion of 3^n-2^n contains no pair of neighbor equal digits (probably finite).

0, 1, 2, 3, 4, 7, 8, 9, 10, 12, 13, 15, 18, 20, 21, 22, 23, 24, 26, 27, 29, 37, 50

Offset

0,3

Links

Table of n, a(n) for n=0..22.

Example

50 is a term because 3^50-2^50 = 717897986565952681927625,
while 49 is not because 3^49-2^49 = 2392(99)328(66)7(66)7576168(77)1 (four pairs of neighbor equal digits).

Mathematica

Reap[Do[id=IntegerDigits[3^m-2^m]; rm=Rest[id]-Most[id]; If[FreeQ[rm, 0], Sow[m]], {m, 0, 10000}]][[2, 1]]

Crossrefs

Cf. A050723 (2^n), A050724 (3^n), A171550 (3^n+2^n).

Sequence in context: A121405 A330217 A231003 * A096199 A104576 A332485

Adjacent sequences: A171548 A171549 A171550 * A171552 A171553 A171554

Keyword

base,fini,full,nonn

Author

Zak Seidov, Dec 11 2009

Status

approved