A075538 a(1)=1, a(2)=2, then use "merge and minus": a(n)=merge(a(1),...,a(n-1))-a(1)-...-a(n-1).

1, 2, 9, 117, 128988, 129116999871, 129117128987999999870883, 129117128988129116999870999999999999870882871012, 129117128988129116999871129117128987999999870882999999999999999999999999870882871011870883000129

Offset

1,2

Comments

A rapidly growing sequence.

Links

Table of n, a(n) for n=1..9.

Formula

a(1)=1, a(2)=2, a(n)=merge(a(1), ..., a(n-1))-a(1)-...-a(n-1).

Example

a(3)=9 because a(1)=1,a(2)=2 and a(3)=merge(a(1),a(2))-a(1)-a(2)=12-1-2=9; then a(4)=117 because a(4)=merge(a(1),a(2),a(3))-a(1)-a(2)-a(3)=129-1-2-9=117.

Mathematica

se={1, 2}; a=1; b=2; me=ToString[a]<>ToString[b]; su=a+b; Do[ab=ToExpression[me]-su; se=Append[se, ab]; su=su+ab; me=ToString[me]<>ToString[ab], {i, 10}]; se

Crossrefs

Cf. A075537.

Sequence in context: A039718 A307249 A201381 * A067965 A237999 A194017

Adjacent sequences: A075535 A075536 A075537 * A075539 A075540 A075541

Keyword

nonn

Author

Zak Seidov, Sep 20 2002

Status

approved