A100787 First differences give the same sequence written as a string of individual digits.

1, 2, 4, 8, 16, 17, 23, 24, 31, 33, 36, 38, 42, 45, 46, 49, 52, 55, 61, 64, 72, 76, 78, 82, 87, 91, 97, 101, 110, 115, 117, 122, 127, 133, 134, 140, 144, 151, 153, 160, 166, 173, 181, 189, 191, 199, 206, 215, 216, 225, 232, 233, 233, 234, 235, 236, 236, 237, 238, 243

Offset: 1

Author

David W. Wilson, Jan 04 2005

Keywords

• base
• easy
• nonn

Examples

			1.2.4.8.16.17.23.24.31 ... <- sequence
.1.2.4.8..1..6..1..7... <- first differences are the sequence's digits.
		

References

• E. Angelini, "Jeux de suites", in Dossier Pour La Science, pp. 32-35, Volume 59 (Jeux math'), April/June 2008, Paris.

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

First differences are A100880; Cf. A100787, A107974, A107975, A107976, A107977 for "seeds" 1, 3, 5, 7 and 9.

Programs

Maple

A[1]:= 1: S:= "1":
for n from 2 to 100 do
  A[n]:= A[n-1] + parse(S[n-1]);
  S:= cat(S, A[n]);
od:
seq(A[i], i=1..100); # Robert Israel, Jun 11 2019

Mathematica

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 *)