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 A015977 Two iterations of Reverse and Add are needed to reach a palindrome. 2
 5, 6, 7, 8, 9, 19, 28, 37, 39, 46, 48, 49, 55, 57, 58, 64, 66, 67, 73, 75, 76, 82, 84, 85, 91, 93, 94, 109, 119, 129, 139, 149, 150, 151, 152, 153, 154, 159, 160, 161, 162, 163, 169, 170, 171, 172, 173, 179, 189, 208, 218, 219, 228, 229, 238, 239, 248 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS The number of iterations starts at 1, so palindromes (cf. A002113) are not excluded. The corresponding sequence excluding palindromes is A065207. LINKS Harvey P. Dale, Table of n, a(n) for n = 0..1000 Index entries for sequences related to Reverse and Add! MATHEMATICA Select[Range[250], Boole[PalindromeQ/@Rest[NestList[#+IntegerReverse[#]&, #, 2]]] == {0, 1}&] (* Harvey P. Dale, May 11 2022 *) PROG (Python) def ra(n): s = str(n); return int(s) + int(s[::-1]) def ispal(n): s = str(n); return s == s[::-1] def aupto(limit): alst = [] for k in range(limit+1): k2 = ra(k) if ispal(k2): continue if ispal(ra(k2)): alst.append(k) return alst print(aupto(250)) # Michael S. Branicky, May 06 2021 CROSSREFS Cf. A002113, A065207. Sequence in context: A125298 A037362 A102717 * A294239 A250050 A051052 Adjacent sequences: A015974 A015975 A015976 * A015978 A015979 A015980 KEYWORD nonn,base AUTHOR Robert G. Wilson v STATUS approved

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Last modified July 25 01:41 EDT 2024. Contains 374585 sequences. (Running on oeis4.)