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A332985 Index of triangular numbers that are sum of two pentagonal numbers (A332984). 2

%I #10 Mar 09 2020 20:58:30

%S 3,4,8,14,32,34,41,42,46,47,49,53,58,63,66,67,69,71,76,79,82,86,89,90,

%T 100,101,102,110,113,117,124,129,141,151,159,168,175,178,183,186,192,

%U 195,205,216,217,219,232,241,247,250,252,253,255,258,261,263,265,271,284,293,297,298

%N Index of triangular numbers that are sum of two pentagonal numbers (A332984).

%C The index of a triangular number T is the integer n such that T = n*(n+1)/2.

%H Peter Kagey, <a href="/A332985/b332985.txt">Table of n, a(n) for n = 1..1000</a>

%Y Cf. A000217 (triangular numbers), A000326 (pentagonal numbers), A332987 (sums of two nonzero pentagonal numbers).

%K nonn,easy

%O 1,1

%A _Olivier GĂ©rard_, Mar 05 2020

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Last modified April 19 16:03 EDT 2024. Contains 371794 sequences. (Running on oeis4.)