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A071240 Arithmetic mean of k and R(k) where k is a number using all odd digits and R(k) is its digit reversal (A004086). 2
1, 3, 5, 7, 9, 11, 22, 33, 44, 55, 22, 33, 44, 55, 66, 33, 44, 55, 66, 77, 44, 55, 66, 77, 88, 55, 66, 77, 88, 99, 111, 212, 313, 414, 515, 131, 232, 333, 434, 535, 151, 252, 353, 454, 555, 171, 272, 373, 474, 575, 191, 292, 393, 494, 595, 212, 313, 414, 515, 616 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..59.

FORMULA

{k + R(k)}/2 where k uses only odd digits 1, 3, 5, 7 and 9.

MAPLE

reversal := proc(n) local i, len, new, temp: new := 0: temp := n: len := floor(log[10](n+.1))+1: for i from 1 to len do new := new+irem(temp, 10)*10^(len-i): temp := floor(temp/10): od: RETURN(new): end: allodd := proc(n) local i, flag, len, temp: temp := n: flag := 1: if n=0 then flag := 0 fi: len := floor(log[10](n+.1))+1: for i from 1 to len do if irem(temp, 10) mod 2 = 1 then temp := floor(temp/10) else flag := 0 fi: od: RETURN(flag): end: for n from 1 to 501 by 2 do if allodd(n) = 1 then printf(`%d, `, (n+reversal(n))/2) fi: od: # James A. Sellers, May 28 2002

CROSSREFS

Cf. A071241, A071242.

Sequence in context: A211138 A178995 A346604 * A088049 A229364 A029660

Adjacent sequences:  A071237 A071238 A071239 * A071241 A071242 A071243

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, May 20 2002

EXTENSIONS

More terms from James A. Sellers, May 28 2002

STATUS

approved

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Last modified December 8 19:10 EST 2021. Contains 349596 sequences. (Running on oeis4.)