A032945 Numbers k whose base-10 representation Sum_{i=0..m} d(i)*10^(m-i) has d(i)=0 for all odd i. Here m is the position of the lead digit of k.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 400, 401, 402, 403

Offset

1,3

Comments

Every nonnegative integer can be represented as the sum of two members of this sequence. - Franklin T. Adams-Watters, Aug 30 2014

This first differs from A236402 at a(110)=1000 (followed by 1010, 1020, 1030, ...), while A236402(110)=910 (followed by 1000, 1001, 1002, ...). - M. F. Hasler, Dec 28 2014

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

N:= 6: # to get all terms with up to N digits
A[1]:= 0:
count:= 1:
for d from 1 to N do
   dp:= ceil(d/2);
   for j from 10^(dp-1) to 10^dp-1 do
      L:= ListTools[Reverse](convert(j, base, 10));
      L:= ListTools[Interleave](L, [0$(d-dp)]);
      count:= count+1;
      A[count]:= add(L[i]*10^(d-i), i=1..d);
    od
od:
seq(A[i], i=1..count); # Robert Israel, Aug 31 2014

Prog

(PARI) is(n)=!forstep(i=2, #n=digits(n), 2, n[i]&&return) \\ M. F. Hasler, Dec 28 2014
(Python)
def ok(n): return str(n)[1::2].strip('0') == ""
print([k for k in range(404) if ok(k)]) # Michael S. Branicky, Apr 12 2022

Crossrefs

Cf. A126684.

Sequence in context: A107085 A212499 A244890 * A236402 A052018 A352461

Adjacent sequences: A032942 A032943 A032944 * A032946 A032947 A032948

Keyword

nonn,base

Author

Clark Kimberling

Extensions

Definition corrected by Franklin T. Adams-Watters, Aug 30 2014

Status

approved