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A332987 Sums of two nonzero pentagonal numbers. 7

%I #19 Jun 15 2021 10:46:01

%S 2,6,10,13,17,23,24,27,34,36,40,44,47,52,56,57,63,70,71,73,75,82,86,

%T 92,93,97,102,104,105,114,118,121,122,127,129,139,140,143,146,150,152,

%U 157,162,167,168,177,180,181,184,187,188,196,198,209,211,215,222,227

%N Sums of two nonzero pentagonal numbers.

%H Peter Kagey, <a href="/A332987/b332987.txt">Table of n, a(n) for n = 1..10000</a>

%t Module[{nn=15,pn},pn=PolygonalNumber[5,Range[nn]];Select[Union[ Total/@ Tuples[ pn,2]],#<=Last[pn]&]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jun 15 2021 *)

%Y Cf. A000326 (pentagonal numbers).

%Y Analogs are A000404 (square numbers), A051533 (triangular numbers), A286636 (centered square numbers), A287960 (centered triangular numbers), A288631 (square pyramidal numbers).

%K nonn

%O 1,1

%A _Olivier GĂ©rard_, Mar 05 2020

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Last modified March 28 15:28 EDT 2024. Contains 371254 sequences. (Running on oeis4.)