OFFSET
0,2
REFERENCES
A. Murthy, Smarandache Notions Journal, Vol. 11 N. 1-2-3 Spring 2000
EXAMPLE
139 belongs to the sequence because it is the concatenation of 3^0, 3^1 and 3^2.
MAPLE
From R. J. Mathar, Oct 10 2010: (Start)
cat2 := proc(a, b) dgsb := max(1, ilog10(b)+1) ; a*10^dgsb+b ; end proc:
catL := proc(L) local a; a := op(1, L) ; for i from 2 to nops(L) do a := cat2(a, op(i, L)) ; end do; a; end proc:
# second Maple program:
a:= proc(n) a(n):= `if`(n<0, 0, parse(cat(a(n-1), 3^n))) end:
seq(a(n), n=0..12); # Alois P. Heinz, May 30 2021
MATHEMATICA
With[{p3=3^Range[0, 15]}, Table[FromDigits[Flatten[IntegerDigits/@ Take[ p3, n]]], {n, 15}]] (* Harvey P. Dale, Sep 13 2011 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Felice Russo, Nov 15 1999
EXTENSIONS
Terms n>=7 corrected by R. J. Mathar, Oct 10 2010
STATUS
approved