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Tag Archives: Pentagonal number
Num3er 1258723
A Pentagonal number is a polygonal number of the form is a prime number. is also prime index of a 13digital palindromic pentagonal number … Continue reading
Posted in Prime Numbers
Tagged Beautiful Number, Pentagonal number, Polygonal number
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Triangular numbers which are the sum of 3 pentagonal numbers
Pentagonal numbers: Let represent the nth triangular number and the nth pentagonal number For any integer , if , then the sum equals since … Continue reading
Primitive Pythagorean triples with the odd leg a Pentagonal number
There are infinitely many primitive Pythagorean triples , like , with hypotenuse c such that the odd leg is a pentagonalnumber and the even leg is consecutive with the hypotenuse. The odd leg a being … Continue reading
Octagonal number and its complementary Pentagonal number
An integer of the form is called a Pentagonal number An integer of the form is called an Octagonal number if then and are said to be complements of … Continue reading
Posted in Number Puzzles
Tagged Octagonal number, Pentagonal number, Polygonal number
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Pentagonals (P(2), P(A), P(B)) in arithmetic progression
If , then c. d. is the common difference c. d. = c. d. = c. d. = c. d. = … Continue reading
Pentagonals (P(1), P(A), P(B)) in arithmetic progression
If , then Here are the first few solutions: = common difference
The smallest pairs of triangular & pentagonal numbers
Find the smallest pair of … (1) … triangular numbers whose sum and difference is triangular (2) … pentagonal numbers whose sum and difference is pentagonal … Continue reading
Harmonic mean between two consecutive triangular numbers is Pentagonal
An integer of the form is called a Triangular number. An integer of the form is called a Pentagonal number. To find such that the Harmonic mean between two consecutive … Continue reading
Difference between an Oblong number and Pentagonal is 1
Oblong numbers are of the form , where is the nth triangular number. An integer of the form is called a Pentagonal number. The first few solutions are : … Continue reading
Pentagonal = 2*(Triangular) or Triangular = 2*Pentagonal
An integer of the form is called a Triangular number. An integer of the form is called a Pentagonal number. Part 1 Part 2 There … Continue reading