OFFSET
1,2
EXAMPLE
a(1)=1: 1;
a(2)=5: 2->5;
a(3)=13: 3->10->13;
a(4)=25: 4->15->22->25;
a(5)=39: 5->20->30->36->39;
a(6)=61: 6->25->40->51->58->61;
a(7)=79: 7->30->45->60->69->76->79;
a(8)=103: 8->35->54->70->84->93->100->103;
a(9)=133: 9->40->63->84->100->112->123->130->133;
a(10)=169: 10->45->72->98->120->135->148->159->166->169.
MATHEMATICA
f[n_] := Fold[#2*Ceiling[#1/#2 + 3] &, n, Reverse@ Range[n - 1]]; Array[f, 49]
PROG
(PARI) a(n)=local(A=n, D); for(i=1, n-1, D=n-i; A=D*ceil(A/D+3)); A
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 12 2005
STATUS
approved