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 A022510 Describe previous term from the right (method A - initial term is 6). 0
 6, 16, 1611, 211611, 21162112, 122112162112, 122112161112212211, 2122112231161112212211, 21221122311621132221221112, 12312211321321121621132221221112 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Method A = 'frequency' followed by 'digit'-indication. LINKS EXAMPLE E.g., the term after 1611 is obtained by saying "two 1's, one 6, one 1", which gives 211611. MATHEMATICA a[1]=6; a[n_]:= a[n]= IntegerReverse[ FromDigits[ Flatten[ Replace[ Replace[ Replace[ Split[ IntegerDigits[a[n-1]]], {x_, y_}->{x, Length[{x, y}]}, {1}], {x_, y_, z_}->{x, Length[{x, y, z}]}, {1}], {x_}->{x, Length[{x}]}, {1}]]]]; Array[a, 10] (* Ivan N. Ianakiev, Jul 23 2019 *) PROG (Python) from re import split A022510_list, l = [6], '6' for _ in range(10):     l = ''.join(str(len(d))+d[0] for d in split('(0+|1+|2+|3+|4+|5+|6+|7+|8+|9+)', l[::-1]) if d)     A022510_list.append(int(l)) # Chai Wah Wu, Jan 02 2015 CROSSREFS Cf. A022506, A006711, A022482, A022507, A022508, A022509, A022511, A022512, A022513. Sequence in context: A001143 A177365 A138490 * A065776 A323516 A120930 Adjacent sequences:  A022507 A022508 A022509 * A022511 A022512 A022513 KEYWORD nonn,base,easy,nice AUTHOR EXTENSIONS More terms from Erich Friedman STATUS approved

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Last modified December 2 16:46 EST 2020. Contains 338877 sequences. (Running on oeis4.)