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 A154770 a(n+1) = A154771(a(n)) = sum of all distinct "valid substrings" of a(n); a(1)=10 (least nontrivial choice). 4
 10, 11, 12, 15, 21, 24, 30, 33, 36, 45, 54, 63, 72, 81, 90, 99, 108, 127, 176, 283, 407, 458, 578, 733, 849, 1003, 1117, 1381, 2044, 2318, 2953, 4397, 5435, 6557, 7964, 9989, 12279, 16572, 26426, 36970, 49970, 67738, 84716, 100181, 111599, 139413, 209606 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS "Valid substrings" means all numbers that appear as substring of n (written in decimal system). Starting values < 10 would yield a constant sequence. LINKS E. Angelini, Sum of all valid substrings (VS), SeqFan list, Jan 16 2009 EXAMPLE a(1) = 10 has { 0, 1, 10 } as distinct substrings, a(2) = 0+1+10 = 11 has { 1, 11 } as distinct substrings, a(3) = 1+11 = 12 has { 1, 2, 12 } as distinct substrings, a(4) = 1+2+12 = 15 has { 1, 5, 15 } as distinct substrings. PROG (PARI) A154770( n=2, a=10 ) = { local(d); while( n--, a=vecsort(concat(vector(d=#Str(a), i, vector(d, j, a%10^j)+(d--&!a\=10))), NULL, 8); a*=vector(#a, i, 1)~); a } print1(a=10); for(i=1, 50, print1(", " a=A154770(, a))) CROSSREFS Cf. A004207, A154771. Sequence in context: A109279 A258744 A219251 * A320601 A305130 A098395 Adjacent sequences:  A154767 A154768 A154769 * A154771 A154772 A154773 KEYWORD base,easy,nonn AUTHOR Eric Angelini and M. F. Hasler, Jan 16 2009 EXTENSIONS The word "distinct" added to definition Jan 19 2009 at the suggestion of Hugo van der Sanden. STATUS approved

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Last modified September 19 09:05 EDT 2019. Contains 327190 sequences. (Running on oeis4.)