cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A071366 Numbers n such that A046523(n) <> A071364(n) and A071364(n) <> n.

Original entry on oeis.org

50, 75, 98, 126, 147, 198, 234, 242, 245, 250, 294, 306, 338, 342, 350, 363, 375, 378, 414, 490, 500, 507, 522, 525, 550, 558, 578, 588, 594, 605, 650, 666, 686, 702, 722, 726, 735, 738, 756, 774, 825, 845, 846, 847, 850, 867, 882, 918, 950, 954, 975, 980
Offset: 1

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Author

Reinhard Zumkeller, May 21 2002

Keywords

Comments

Also A046523(n) <> n, as A046523(n) <= A071364(n) <= n.

Examples

			n=50=2*5*5: A071364(50)=2*3*3=18, A046523(50)=2*2*3=12;
n=500=2*2*5*5*5: A071364(500)=2*2*3*3*3=108, A046523(500)=2*2*2*3*3=72.
		

Crossrefs

Cf. A071365.

Programs

  • Mathematica
    Select[Range[1000], (e = Last /@ FactorInteger[ # ]) != Sort[e, Greater] && Product[Prime[i]^e[[i]], {i, Length[e]}] != # &] (* Ray Chandler, Sep 23 2005 *)

Extensions

Extended by Ray Chandler, Sep 23 2005