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A155047
a(1) = 1, a(2) = 2, then a(n) = largest prime factor of the partial sum up to a(n-1).
1
1, 2, 3, 3, 3, 3, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 11, 11, 11, 11, 11, 11, 13, 13, 13, 13, 13, 13, 17, 17, 17, 17, 17, 17, 19, 19, 19, 19, 19, 19, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 29, 29, 29, 29, 29, 29, 29, 29, 31, 31, 31, 31, 31, 31, 31, 31, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 41
OFFSET
1,2
LINKS
MAPLE
A006530 := proc(n) max(op(numtheory[factorset](n))) ; end:
A155047 := proc(n) option remember; if n <=2 then n; else A006530( add(procname(i), i=1..n-1)) ; fi; end:
seq(A155047(n), n=1..120) ; # R. J. Mathar, Oct 23 2009
MATHEMATICA
nxt[{t_, a_}]:=Module[{lpf=FactorInteger[t][[-1, 1]]}, {t+lpf, lpf}]; Join[ {1}, NestList[ nxt, {3, 2}, 80][[All, 2]]] (* Harvey P. Dale, Aug 06 2018 *)
CROSSREFS
Sequence in context: A056206 A257245 A329245 * A369451 A029088 A253591
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Jan 19 2009
EXTENSIONS
Extended by R. J. Mathar, Oct 23 2009
STATUS
approved