%I #17 Jul 07 2024 13:57:18
%S 1,3,5,7,9,11,22,33,44,55,22,33,44,55,66,33,44,55,66,77,44,55,66,77,
%T 88,55,66,77,88,99,111,212,313,414,515,131,232,333,434,535,151,252,
%U 353,454,555,171,272,373,474,575,191,292,393,494,595,212,313,414,515,616
%N Arithmetic mean of k and R(k) where k is a number using only odd digits and R(k) is its digit reversal (A004086).
%F {k + R(k)}/2 where k uses only odd digits 1, 3, 5, 7 and 9.
%F a(n) = (A014261(n) + A004086(A014261(n))) / 2. - _Sean A. Irvine_, Jul 06 2024
%p reversal := proc(n) local i, len, new, temp:
%p new := 0: temp := n: len := floor(log[10](n+.1))+1:
%p for i from 1 to len do
%p new := new+irem(temp, 10)*10^(len-i):
%p temp := floor(temp/10):
%p od:
%p RETURN(new):
%p end:
%p allodd := proc(n) local i, flag, len, temp:
%p temp := n: flag := 1: if n=0 then flag := 0 fi: len := floor(log[10](n+.1))+1:
%p for i from 1 to len do
%p if irem(temp, 10) mod 2 = 1 then temp := floor(temp/10) else flag := 0 fi:
%p od:
%p RETURN(flag):
%p end:
%p for n from 1 to 501 by 2 do
%p if allodd(n) = 1 then printf(`%d, `, (n+reversal(n))/2) fi:
%p od: # _James A. Sellers_, May 28 2002
%Y Cf. A004086, A014261, A071241, A071242.
%K base,nonn
%O 0,2
%A _Amarnath Murthy_, May 20 2002
%E More terms from _James A. Sellers_, May 28 2002