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A164531
a(1)=1. a(n) = the smallest multiple of d(n) that is >= a(n-1), where d(n) = the number of positive divisors of n.
2
1, 2, 2, 3, 4, 4, 4, 4, 6, 8, 8, 12, 12, 12, 12, 15, 16, 18, 18, 18, 20, 20, 20, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 27, 28, 28, 28, 32, 32, 32, 32, 36, 36, 36, 36, 40, 42, 42, 44, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 49, 52, 56, 56, 60, 60, 64, 64, 72, 72
OFFSET
1,2
LINKS
MATHEMATICA
Block[{n = 1, d}, NestList[(d = DivisorSigma[0, ++n]) * Ceiling[# / d] &, 1, 100]] (* Paolo Xausa, Mar 21 2024 *)
PROG
(PARI)
A164531_list(nmax)={my(A=vector(nmax)); A[1]=1;
for(k=2, nmax, my(i=1); while(numdiv(k)*i<A[k-1], i+=1); A[k]=numdiv(k)*i); A}
A164531_list(100) \\ John Tyler Rascoe, Mar 20 2024
CROSSREFS
Sequence in context: A340619 A334800 A228942 * A138161 A307483 A034136
KEYWORD
nonn,easy
AUTHOR
Leroy Quet, Aug 15 2009
EXTENSIONS
Extended by Ray Chandler, Mar 15 2010
STATUS
approved