A225070 - OEIS

A225070

Least decagonal (10-gonal) number that is the product of n decagonal numbers greater than 1.

10, 69300, 9729720, 4257000, 967412160, 4104100000, 1408951239696000, 59860503846000000, 1542547619019487080000, 39054496014386012160000, 450510331438947780000000

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..11.

Lars Blomberg, Table of n, a(n) with solutions for n=1..11

EXAMPLE

Let dec(n) = n*(4n-3). Then

a(1) = 10 = dec(2).

a(2) = 69300 = dec(132) = dec(2) * dec(42).

a(3) = 9729720 = dec(1560) = dec(3) * dec(4) * dec(42).

a(4) = 4257000 = dec(1032) = dec(2)^3 * dec(33).

a(5) = 967412160 = dec(15552) = dec(2) * dec(3) * dec(4) * dec(8) * dec(9).

a(6) = 4104100000 = dec(32032) = dec(2)^3 * dec(4) * dec(7) * dec(11).

CROSSREFS

Cf. A001107 (decagonal numbers).

Cf. A212616, A212617, A225066-A225069 (3-, 5- to 9-gonal cases).

Sequence in context: A055310 A371644 A048832 * A115673 A225720 A013792

Adjacent sequences: A225067 A225068 A225069 * A225071 A225072 A225073

KEYWORD

nonn,more

AUTHOR

T. D. Noe, May 01 2013

EXTENSIONS

Corrected a(6) and added a(7)-a(11) by Lars Blomberg, Sep 20 2013

STATUS

approved