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A038841
Concatenation of prime factors of n is a cube.
0
14, 129, 203, 394, 403, 7654, 12977, 14055, 19582, 46595, 48230, 53962, 62545, 84139, 84769, 95655, 100094, 192364, 211841, 250630, 267051, 279385, 449377, 549601, 655945, 705274, 713530, 827359, 841033, 879203, 1130825, 1179435, 1236865
OFFSET
1,1
COMMENTS
Arguably, 1 should be included in this sequence.
Prime factors taken with multiplicity. - Harvey P. Dale, Nov 28 2014
EXAMPLE
62545=5*7*1787 and 571787=83^3.
MATHEMATICA
cpfQ[n_]:=IntegerQ[Surd[FromDigits[Flatten[IntegerDigits/@Flatten[ Table[#[[1]], {#[[2]]}]&/@FactorInteger[n]]]], 3]]; Select[Range[1250000], cpfQ] (* Harvey P. Dale, Nov 28 2014 *)
PROG
(PARI) catpf(n)=my(f=factor(n), s=""); for(i=1, #f[, 1], for(j=1, f[i, 2], s=Str(s, f[i, 1]))); eval(s)
for(n=2, 1e7, if(ispower(catpf(n), 3), print1(n", ")))
CROSSREFS
Sequence in context: A208047 A301379 A222571 * A240189 A021354 A208427
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
Corrected and extended; also program from Charles R Greathouse IV, Apr 28 2010
STATUS
approved