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A134268
a(n+2) = sum_digits[a(n+1)] + sum_digits[a(n)] + sum_digits[a(n+1)]*sum_digits[a(n)], with a(0)=0, a(1)=1.
2
0, 1, 3, 19, 54, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153, 109, 120, 55, 153
OFFSET
0,3
COMMENTS
Period [153,109,120,55] after 6 terms. - Georg Fischer, Aug 22 2020
MAPLE
P:=proc(n)local a0, a1, i, k, w, x; a0:=0; a1:=1; print(a0); print(a1); for i from 1 by 1 to n do w:=0; k:=a0+a1; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; x:=0; k:=a1; while k>0 do x:=x+k-(trunc(k/10)*10); k:=trunc(k/10); od; a0:=a1; a1:=w+x+w*x; print(a1); od; end: P(100);
MATHEMATICA
PadRight[{0, 1, 3, 19, 54}, 100, {153, 109, 120, 55}] (* Harvey P. Dale, Aug 03 2023 *)
CROSSREFS
Cf. A010077.
Sequence in context: A222185 A265774 A100697 * A322209 A088798 A027272
KEYWORD
easy,nonn,base
AUTHOR
STATUS
approved