

A316858


Triangle read by rows constructed from A090368 as sum of least prime factors.


1



6, 8, 8, 10, 10, 10, 6, 12, 12, 6, 14, 8, 14, 8, 14, 16, 16, 10, 10, 16, 16, 6, 18, 18, 6, 18, 18, 6, 20, 8, 20, 14, 14, 20, 8, 20, 22, 22, 10, 16, 22, 16, 10, 22, 22, 6, 24, 24, 6, 24, 24, 6, 24, 24, 6, 26, 8, 26, 20, 14, 26, 14, 20, 26, 8, 26, 8, 28, 10, 22, 28, 16, 16, 28, 22, 10, 28, 8
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OFFSET

1,1


COMMENTS

The greatest number in row k is 2*k + 4, thus consecutive rows identify consecutive even numbers (sums of two primes).
To get the nth row: copy (1...n) of A090368, reverse, and add together.
When primes meet primes we get the maximum values. When primes or prime factors meet prime factors, we get lesser values. (Spot checked. Still empirical.)


LINKS



EXAMPLE

Triangle begins:
{ 6}, < copy (1,1) of A090368, add together
{ 8, 8}, < copy (1,2) of A090368, reverse, and add together
{10, 10, 10}, < copy (1,3) of A090368, reverse, and add together
{ 6, 12, 12, 6},
{14, 8, 14, 8, 14},
{16, 16, 10, 10, 16, 16},
{ 6, 18, 18, 6, 18, 18, 6}, <=== differences from A316859 begin here
{20, 8, 20, 14, 14, 20, 8, 20},
{22, 22, 10, 16, 22, 16, 10, 22, 22},
{ 6, 24, 24, 6, 24, 24, 6, 24, 24, 6},
{26, 8, 26, 20, 14, 26, 14, 20, 26, 8, 26},
{ 8, 28, 10, 22, 28, 16, 16, 28, 22, 10, 28, 8}


MATHEMATICA

lpf[n_] := FactorInteger[2 n + 1][[1, 1]]; A090368 = Array[lpf, 12];


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



