A038841 Concatenation of prime factors of n is a cube.

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

Links

Table of n, a(n) for n=1..33.

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

Adjacent sequences: A038838 A038839 A038840 * A038842 A038843 A038844

Keyword

nonn,base

Author

Jeff Burch

Extensions

Corrected and extended; also program from Charles R Greathouse IV, Apr 28 2010

Status

approved