A113603 Numbers obtained as the sum mod 10 of corresponding digits of n and its digit reversal.

2, 4, 6, 8, 0, 2, 4, 6, 8, 11, 22, 33, 44, 55, 66, 77, 88, 99, 0, 22, 33, 44, 55, 66, 77, 88, 99, 0, 11, 33, 44, 55, 66, 77, 88, 99, 0, 11, 22, 44, 55, 66, 77, 88, 99, 0, 11, 22, 33, 55, 66, 77, 88, 99, 0, 11, 22, 33, 44, 66, 77, 88, 99, 0, 11, 22, 33, 44, 55, 77, 88, 99, 0, 11, 22

Offset

1,1

Comments

Most of the terms are palindromes except for the case when the most significant digit sum == 0 mod 10.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Example

a(2358) = 0880. Digit reversal of 2358 is 8532 and the corresponding digit sums mod 10 are 8+2 == 0, 5+3 == 8, 5+3 == 8, 8+2 == 0.

Maple

A113603 := proc(n)
        dgs := convert(n, base, 10) ;
        dmod10 := [] ;
        for i from 1 to nops(dgs) do
                dmod10 := [op(dmod10), (op(i, dgs)+op(-i, dgs)) mod 10 ] ;
        end do;
        add( op(i, dmod10)*10^(i-1), i=1..nops(dmod10)) ;
end proc:
seq(A113603(n), n=1..90) ; # R. J. Mathar, Oct 01 2011
# second Maple program:
a:= n-> (s-> parse(cat(seq(parse(s[i])+parse(s[-i])
             mod 10, i=1..length(s)))))(""||n):
seq(a(n), n=1..100);  # Alois P. Heinz, Aug 09 2015

Mathematica

Table[FromDigits[Mod[Total[#], 10]&/@Thread[{IntegerDigits[n], Reverse[IntegerDigits[n]]}]], {n, 80}] (* Harvey P. Dale, Sep 05 2023 *)

Crossrefs

Cf. A113602.

Sequence in context: A317647 A243590 A169933 * A004520 A169918 A169916

Adjacent sequences: A113600 A113601 A113602 * A113604 A113605 A113606

Keyword

base,easy,less,nonn

Author

Amarnath Murthy, Nov 09 2005

Status

approved