A378493 Dot product of the first n primes and the first n triangular numbers.

2, 11, 41, 111, 276, 549, 1025, 1709, 2744, 4339, 6385, 9271, 13002, 17517, 23157, 30365, 39392, 49823, 62553, 77463, 94326, 114313, 137221, 163921, 195446, 230897, 269831, 313273, 360688, 413233, 476225, 545393, 622250, 704955, 798825, 899391, 1009762

Offset: 1

Author

Harvey P. Dale, Nov 28 2024

Keywords

• nonn

Examples

			a(3) = dot product of {2,3,5} and {1,3,6} = 2*1+3*3+5*6 = 41.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000 (first 1000 terms from Harvey P. Dale)

Crossrefs

Partial sums of A196421.

Cf. A000040, A000217, A166486.

Programs

Maple

a:= proc(n) option remember; `if`(n<1, 0,
      a(n-1)+ithprime(n)*n*(n+1)/2)
    end:
seq(a(n), n=1..37);  # Alois P. Heinz, Nov 28 2024

Mathematica

Table[Prime[Range[n]].Accumulate[Range[n]],{n,50}]

Formula

a(n) mod 2 = A166486(n-1).