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%I #13 Jun 11 2019 22:43:46
%S 1,2,4,8,16,17,23,24,31,33,36,38,42,45,46,49,52,55,61,64,72,76,78,82,
%T 87,91,97,101,110,115,117,122,127,133,134,140,144,151,153,160,166,173,
%U 181,189,191,199,206,215,216,225,232,233,233,234,235,236,236,237,238,243
%N First differences give the same sequence written as a string of individual digits.
%D E. Angelini, "Jeux de suites", in Dossier Pour La Science, pp. 32-35, Volume 59 (Jeux math'), April/June 2008, Paris.
%H Robert Israel, <a href="/A100787/b100787.txt">Table of n, a(n) for n = 1..10000</a>
%e 1.2.4.8.16.17.23.24.31 ... <- sequence
%e .1.2.4.8..1..6..1..7... <- first differences are the sequence's digits.
%p A[1]:= 1: S:= "1":
%p for n from 2 to 100 do
%p A[n]:= A[n-1] + parse(S[n-1]);
%p S:= cat(S, A[n]);
%p od:
%p seq(A[i], i=1..100); # _Robert Israel_, Jun 11 2019
%t a[1] = 1; a[n_] := a[n] = a[n - 1] + Flatten[ Table[ IntegerDigits[ a[i]], {i, n - 1}]][[n - 1]]; Table[ a[n], {n, 60}] (* _Robert G. Wilson v_, Jun 15 2005 *)
%Y First differences are A100880; Cf. A100787, A107974, A107975, A107976, A107977 for "seeds" 1, 3, 5, 7 and 9.
%K base,easy,nonn
%O 1,2
%A _David W. Wilson_, Jan 04 2005
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