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A278227
Least number with the prime signature of prime(n)-1.
4
1, 2, 4, 6, 6, 12, 16, 12, 6, 12, 30, 36, 24, 30, 6, 12, 6, 60, 30, 30, 72, 30, 6, 24, 96, 36, 30, 6, 72, 48, 60, 30, 24, 30, 12, 60, 60, 48, 6, 12, 6, 180, 30, 192, 36, 60, 210, 30, 6, 60, 24, 30, 240, 24, 256, 6, 12, 120, 60, 120, 30, 12, 60, 30, 120, 12, 210, 240, 6, 60, 96, 6, 30, 60, 120, 6, 12, 180, 144, 120, 30, 420, 30, 432, 30, 30, 192, 120, 60, 210
OFFSET
1,2
LINKS
FORMULA
a(n) = A046523(A000040(n)-1).
MATHEMATICA
Table[Times @@ MapIndexed[(Prime@ First@ #2)^#1 &, #] &@ If[Length@ # == 1 && #[[1, 1]] == 1, {0}, Reverse@ Sort@ #[[All, -1]]] &@ FactorInteger[Prime@ n - 1], {n, 120}] (* Michael De Vlieger, Nov 21 2016 *)
PROG
(Scheme) (define (A278227 n) (A046523 (+ -1 (A000040 n))))
CROSSREFS
Cf. also A278228, A278229, A278230.
Sequence in context: A087459 A285103 A123258 * A104968 A286894 A346911
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 19 2016
STATUS
approved