cp's OEIS Frontend

A334008 a(n) is the least integer that can be expressed as the sum of one or more consecutive nonzero pentagonal numbers in exactly n ways.

%I A334008 #11 Feb 16 2025 08:34:00
%S A334008 1,287,472320,89051435880
%N A334008 a(n) is the least integer that can be expressed as the sum of one or more consecutive nonzero pentagonal numbers in exactly n ways.
%H A334008 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PentagonalNumber.html">Pentagonal Number</a>
%H A334008 <a href="/index/Pol#polygonal_numbers">Index to sequences related to polygonal numbers</a>
%e A334008 Let S(k, m) denote the sum of m pentagonal numbers starting from the k-th. We have
%e A334008 a(1) = S(1, 1);
%e A334008 a(2) = S(14, 1) = S(2, 7);
%e A334008 a(3) = S(103, 24) = S(19, 80) = S(67, 41);
%e A334008 a(4) = S(10833, 484) = S(4542, 1936) = S(9153, 660) = S(2817, 3036);
%Y A334008 Cf. A000326, A054859, A068314, A186337, A298467, A319184, A334007, A334010, A334011, A334012.
%K A334008 nonn,hard,more
%O A334008 1,2
%A A334008 _Ilya Gutkovskiy_, Apr 12 2020
%E A334008 a(4) from _Giovanni Resta_, Apr 13 2020