A036328 Composite numbers n such that juxtaposition of prime factors of n has length 4.

16, 24, 36, 40, 44, 52, 54, 56, 60, 66, 68, 76, 78, 81, 84, 90, 92, 99, 100, 102, 110, 114, 116, 117, 121, 124, 126, 130, 135, 138, 140, 143, 148, 150, 153, 154, 164, 165, 169, 170, 171, 172, 174, 182, 186, 187, 188, 189, 190, 195, 196, 202, 206, 207, 209, 210

Offset

1,1

Comments

The last term of this sequence is a(1048)=9409.

Prime factors are taken with multiplicity. - Harvey P. Dale, Dec 05 2015

Links

Nathaniel Johnston, Table of n, a(n) for n = 1..1048 (full sequence)

Maple

isA036328 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=4, n, NULL): end: l:=[seq(isA036328(n), n=2..9999)]; # Nathaniel Johnston, Jun 22 2011

Mathematica

jpf4Q[n_]:=Length[Flatten[IntegerDigits/@Table[#[[1]], {#[[2]]}]&/@FactorInteger[n]]]==4; Select[Range[300], jpf4Q] (* Harvey P. Dale, Dec 05 2015 *)

Crossrefs

Cf. A036326-A036334.

Sequence in context: A163284 A100316 A206260 * A067028 A110893 A014613

Adjacent sequences: A036325 A036326 A036327 * A036329 A036330 A036331

Keyword

nonn,base,fini,full,easy

Author

Patrick De Geest, Dec 15 1998

Status

approved