

A257521


Odd Brazilian numbers.


8



7, 13, 15, 21, 27, 31, 33, 35, 39, 43, 45, 51, 55, 57, 63, 65, 69, 73, 75, 77, 81, 85, 87, 91, 93, 95, 99, 105, 111, 115, 117, 119, 121, 123, 125, 127, 129, 133, 135, 141, 143, 145, 147, 153, 155, 157, 159, 161, 165, 171, 175, 177, 183, 185, 187, 189, 195
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

All even integers 2p >=8 are Brazilian numbers (A125134), because 2p=2(p1)+2 is written 22 in base p1 if p1>2, that is true if p >=4. But, among Brazilian numbers, there are also odd ones...
The only square of a prime is 121.  Robert G. Wilson v, May 21 2015


LINKS

Daniel Lignon and Robert Israel, Table of n, a(n) for n = 1..10000 (first 703 from Daniel Lignon)


MAPLE

N:= 1000: # to get all terms <= N
for b from 2 to floor(N/21) do
dk:= 1 + (b mod 2);
for j from 1 to b1 by 2 do
for k from dk by dk do
if j=1 and k=1 then next fi;
x:= j*(b^(k+1)1)/(b1);
if x > N then break fi;
B[x]:= 1;
od
od
od:
sort(map(op, [indices(B)])); # Robert Israel, May 27 2015


MATHEMATICA

fQ[n_] := Block[{b = 2}, While[b < n  1 && Length[ Union[ IntegerDigits[n, b]]] > 1, b++]; b < n  1]; Select[1 + 2 Range@100, fQ] (* Robert G. Wilson v, May 21 2015 *)


PROG

(PARI) forstep(n=5, 300, 2, for(b=2, n2, d=digits(n, b); if(vecmin(d)==vecmax(d), print1(n, ", "); break))) \\ Derek Orr, Apr 30 2015


CROSSREFS

Cf. A125134 (Brazilian numbers), A253261 (odd Brazilian squares).
Cf. A085104 (prime Brazilian numbers).
Sequence in context: A076196 A167782 A326380 * A053696 A090503 A059520
Adjacent sequences: A257518 A257519 A257520 * A257522 A257523 A257524


KEYWORD

nonn,base,easy


AUTHOR

Daniel Lignon, Apr 27 2015


STATUS

approved



