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A278254
Least number with the prime signature of n^2; square of the least number with the prime signature of n.
9
1, 4, 4, 16, 4, 36, 4, 64, 16, 36, 4, 144, 4, 36, 36, 256, 4, 144, 4, 144, 36, 36, 4, 576, 16, 36, 64, 144, 4, 900, 4, 1024, 36, 36, 36, 1296, 4, 36, 36, 576, 4, 900, 4, 144, 144, 36, 4, 2304, 16, 144, 36, 144, 4, 576, 36, 576, 36, 36, 4, 3600, 4, 36, 144, 4096, 36, 900, 4, 144, 36, 900, 4, 5184, 4, 36, 144, 144, 36, 900, 4, 2304, 256, 36, 4, 3600, 36, 36, 36
OFFSET
1,2
LINKS
FORMULA
a(n) = A046523(n^2) = A046523(n)^2.
a(n) = A278259(2*n).
MATHEMATICA
Table[Times @@ MapIndexed[(Prime@ First@ #2)^#1 &, #] &@ If[Length@ # == 1 && #[[1, 1]] == 1, {0}, Reverse@ Sort@ #[[All, -1]]] &@ FactorInteger[ n^2], {n, 120}] (* Michael De Vlieger, Nov 21 2016 *)
PROG
(Scheme)
(define (A278254 n) (A000290 (A046523 n)))
(define (A278254 n) (A046523 (A000290 n)))
(PARI) a(n)=my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i])^2 \\ Charles R Greathouse IV, Feb 03 2017
CROSSREFS
Bisection of A278259.
Sequence in context: A217954 A273749 A273563 * A091278 A127473 A375745
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 19 2016
STATUS
approved