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.

A277323 Even bisection of A260443 (the odd terms): a(n) = A260443(2*n).

Original entry on oeis.org

1, 3, 5, 15, 7, 75, 35, 105, 11, 525, 245, 2625, 77, 3675, 385, 1155, 13, 5775, 2695, 128625, 847, 643125, 18865, 202125, 143, 282975, 29645, 1414875, 1001, 444675, 5005, 15015, 17, 75075, 35035, 15563625, 11011, 346644375, 2282665, 108945375, 1859, 544726875, 15978655, 12132553125, 121121, 3813088125, 2697695
Offset: 0

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Author

Antti Karttunen, Oct 10 2016

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := a[n] = Which[n < 2, n + 1, EvenQ@ n, Times @@ Map[#1^#2 & @@ # &, FactorInteger[#] /. {p_, e_} /; e > 0 :> {Prime[PrimePi@ p + 1], e}] - Boole[# == 1] &@ a[n/2], True, a[#] a[# + 1] &[(n - 1)/2]]; Table[a[2 n], {n, 0, 46}] (* Michael De Vlieger, Apr 05 2017 *)

Formula

a(n) = A260443(2*n).
a(0) = 1; for n >= 1, a(n) = A003961(A260443(n)).
Other identities. For all n >= 0:
A007949(a(n)) = A000035(n).
A112765(a(n)) is the interleaving of A000035 and A005811, probably A101979.