OFFSET
0,1
COMMENTS
a(n) = prime(v(1)) * prime(v(2)) * ... * prime(v(k)), where prime(n) is the n-th prime (= A000040(n)) and v(1) .. v(k) are 2-adic valuations (not all necessarily distinct) of the iterated values obtained when running Shevelev's algorithm for computing A002326. See comments in A179680 and compare to A292265.
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..1023
MATHEMATICA
a265[n_] := n/2^IntegerExponent[n, 2];
a[n_] := Module[{x, z, m}, x = 2 n + 1; z = Prime[IntegerExponent[1 + x, 2]]; m = a265[1 + x]; While[m != 1, z *= Prime[IntegerExponent[x + m, 2]]; m = a265[x + m]]; z];
Table[a[n], {n, 0, 39}] (* Jean-François Alcover, Oct 03 2017, translated from PARI *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 02 2017
STATUS
approved