|
Search: id:A037281
|
|
|
| A037281 |
|
Number of iterations of transformation in A037280 needed to reach 1 or a prime, or -1 if no such number exists. |
|
+0
2
|
|
| 0, 0, 0, 1, 0, 1, 0, 1, 1, 2, 0
(list; graph; listen)
|
|
|
OFFSET
|
1,10
|
|
|
MAPLE
|
with(numtheory):ds:=proc(s) local j: RETURN(add(s[j]*10^(j-1), j=1..nops(s))):end: a:=proc(n) options remember: local d, i, l, m: if n<3 then RETURN(1) else if not isprime(n) then d:=divisors(n): l:=nops(d): m:=ds([seq(op(convert(d[l-i+1], base, 10)), i=2..l-1)]): RETURN(m/piecewise(m mod 2=1, 1, 2^(ifactors(m)[2][1][2]))) else RETURN(n) fi fi: end; for n from 1 to 11 do m:=n: for i from 0 while(not isprime(m) and m<>1) do m:=a(m) od: printf("%d, ", i) od: (Ronaldo)
|
|
CROSSREFS
|
Cf. A037279.
Sequence in context: A118269 A131038 A137979 this_sequence A118626 A062892 A118553
Adjacent sequences: A037278 A037279 A037280 this_sequence A037282 A037283 A037284
|
|
KEYWORD
|
nonn,base,more
|
|
AUTHOR
|
njas
|
|
EXTENSIONS
|
Corrected by C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 29 2004
|
|
|
Search completed in 0.002 seconds
|
