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 A123171 a(1) = 123, a(n) = sum of digits of all previous terms. 0
 123, 6, 12, 15, 21, 24, 30, 33, 39, 51, 57, 69, 84, 96, 111, 114, 120, 123, 129, 141, 147, 159, 174, 186, 201, 204, 210, 213, 219, 231, 237, 249, 264, 276, 291, 303, 309, 321, 327, 339, 354, 366, 381, 393, 408, 420, 426, 438, 453, 465, 480, 492, 507, 519, 534 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(1) = 123 a(2) = 1 + 2 + 3 = 6 a(3) = (1 + 2 + 3) + 6 = 12 a(4) = (1 + 2 + 3) + 6 + (1 + 2) = 15 a(5) = (1 + 2 + 3) + 6 + (1 + 2) + (1 + 5) = 21 a(6) = (1 + 2 + 3) + 6 + (1 + 2) + (1 + 5) + (2 + 1) = 24 a(7) = (1 + 2 + 3) + 6 + (1 + 2) + (1 + 5) + (2 + 1) + (2 + 4) = 30 ... Essentially the same as A016052. - R. J. Mathar, Jun 18 2008 LINKS Sergio Silva, Teste Numerico. FORMULA a(n) = a(n-1) + sum of digits of a(n-1), a(1) = 123 PROG (PARI) s=0; a=123; print1(a, ", "); for(n=1, 100, dig=eval(Vec(Str(a))); s=s+sum(i=1, length(dig), dig[i]); print1(s, ", "); a=s) CROSSREFS Cf. A004207. Sequence in context: A015079 A015042 A062233 * A125097 A302211 A308004 Adjacent sequences:  A123168 A123169 A123170 * A123172 A123173 A123174 KEYWORD nonn,base AUTHOR Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 02 2006 STATUS approved

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Last modified December 13 12:08 EST 2019. Contains 329968 sequences. (Running on oeis4.)