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A328724
a(1)=2, a(2)=3; a(n) is the smallest k > a(n-1) such that k + a(n-1) is a multiple of a(n-2).
1
2, 3, 5, 7, 8, 13, 19, 20, 37, 43, 68, 104, 168, 248, 256, 488, 536, 928, 1216, 1568, 2080, 2624, 3616, 4256, 6592, 10432, 15936, 25792, 37952, 39424, 74432, 83264, 140032, 193024, 227072, 352000, 556288, 851712, 1373440, 2033408, 2086912, 4013312
OFFSET
1,1
COMMENTS
(a(n+1)+a(n+2))/a(n) gives the sequence 4, 4, 3, 3, 4, 3, 3, 4, 3, 4, 4, 4, 3, 3, 4, 3, 4, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 3, 3, 4, 3, 4, 3, 3, 4, 4, 4, 4, 3, 3, 4, 3, 4, 3, 3, 3, 4, 3, ...
LINKS
EXAMPLE
a(7)=19; a(8)=20. 37 is the smallest number, larger than 20, that can be added to 20 and the result (57) is divisible by 19. So, a(9)=37.
MAPLE
A[1]:= 2: A[2]:= 3:
for n from 3 to 50 do
k:= -A[n-1] mod A[n-2];
A[n]:= k + A[n-2]*(1+floor((A[n-1]-k)/A[n-2]));
od:
seq(A[i], i=1..50); # Robert Israel, Oct 27 2019
CROSSREFS
Sequence in context: A080435 A108330 A262587 * A039892 A278645 A352290
KEYWORD
nonn
AUTHOR
Ali Sada, Oct 26 2019
STATUS
approved