A135739 Numbers n such that n+reverse(n) has only odd decimal digits (n not a multiple of 10).

12, 14, 16, 18, 21, 23, 25, 27, 32, 34, 36, 41, 43, 45, 52, 54, 61, 63, 72, 81, 209, 219, 229, 239, 249, 308, 318, 328, 338, 348, 407, 409, 417, 419, 427, 429, 437, 439, 447, 449, 506, 508, 516, 518, 526, 528, 536, 538, 546, 548, 605, 607, 609, 615, 617, 619

Offset

1,1

Comments

Obviously n is in the sequence iff reverse(n) is in the sequence.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Project Euler, Problem 145: How many reversible numbers are there below one-billion?

Example

409 + 904 = 1313 has only odd digits, so 409 and 904 are in the sequence.

Mathematica

odQ[n_]:=Module[{t=Count[IntegerDigits[n+FromDigits[Reverse[IntegerDigits[n]]]], _?EvenQ]}, t==0&&!Divisible[n, 10]]; Select[Range[700], odQ] (* Harvey P. Dale, Feb 20 2013 *)

Prog

(PARI) reverse(n, m)=n=[n]; while(n=divrem(n[1], 10), m=10*m+n[2]); m odd=Vec("13579"); for(i=1, 999, i%10&!setminus(Set(Vec(Str(i+reverse(i)))), odd)&print1(i", "))
(Python)
def ok(n): return n%10 and set(str(n + int(str(n)[::-1]))) <= set("13579")
print([k for k in range(620) if ok(k)]) # Michael S. Branicky, Aug 15 2022

Crossrefs

Sequence in context: A290001 A371422 A080693 * A096923 A141642 A163622

Adjacent sequences: A135736 A135737 A135738 * A135740 A135741 A135742

Keyword

base,easy,nonn

Author

M. F. Hasler, Dec 01 2007, Dec 05 2007

Status

approved