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A240521 a(n) = A050376(n)*A050376(n+1) where A050376(n) is the n-th number of the form p^(2^k) with p is prime and k >= 0. 7
6, 12, 20, 35, 63, 99, 143, 208, 272, 323, 437, 575, 725, 899, 1147, 1517, 1763, 2021, 2303, 2597, 3127, 3599, 4087, 4757, 5183, 5767, 6399, 6723, 7387, 8633, 9797, 10403, 11021, 11663, 12317, 13673, 15367, 16637, 17947, 19043, 20711, 22499, 23707, 25591 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Let S be an odd positive number. The S-sequence of positive numbers is defined to be the sequence {prod_{i=1,...,r} q_(n+t_i)}_{n>=1}, where {q_i} is sequence A050376 and sum_{i=1,...,r} 2^t_i is the binary representation of S, such that t_1>t_2>...>t_r=0. Note that {S_1, S_3, S_5, ...} is a partition of all integers > 1. Then S_1=A050376, which is obtained when we set r=1,t_1=0.

This present sequence is the 3-sequence in this partition. It is obtained when we set r=2, t_1=1, t_2=0.

A minimal set of generators for A000379 as a group under A059897(.,.). - Peter Munn, Aug 11 2019

LINKS

Table of n, a(n) for n=1..44.

Eric Weisstein's World of Mathematics, Group.

Wikipedia, Generating set of a group.

CROSSREFS

Cf. A000379, A050376, A059897.

Sequence in context: A309836 A117343 A286290 * A220211 A028611 A220470

Adjacent sequences:  A240518 A240519 A240520 * A240522 A240523 A240524

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Apr 07 2014

EXTENSIONS

More terms from Peter J. C. Moses, Apr 18 2014

STATUS

approved

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Last modified March 5 15:57 EST 2021. Contains 341825 sequences. (Running on oeis4.)