A289055 Triangle read by rows: T(n,k) = (k+1)*A028815(n) for 0 <= k <= n.

2, 3, 6, 4, 8, 12, 6, 12, 18, 24, 8, 16, 24, 32, 40, 12, 24, 36, 48, 60, 72, 14, 28, 42, 56, 70, 84, 98, 18, 36, 54, 72, 90, 108, 126, 144, 20, 40, 60, 80, 100, 120, 140, 160, 180, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330

Offset: 0

Author

Vincenzo Librandi, Sep 02 2017

Keywords

• nonn
• tabl
• less

Examples

			Triangle begins:
   2;
   3,   6;
   4,   8,  12;
   6,  12,  18,  24;
   8,  16,  24,  32,  40;
  12,  24,  36,  48,  60,  72;
  14,  28,  42,  56,  70,  84,  98;
  18,  36,  54,  72,  90, 108, 126, 144;
  20,  40,  60,  80, 100, 120, 140, 160, 180;
  ...
		

Links

• G. C. Greubel, Rows n = 0..50 of the triangle, flattened

Crossrefs

Cf. A289108.

Columns k: A028815 (k=0), A089241 (k=1), A247159 (k=2), A273801 (k=3).

Programs

Magma

/* As triangle (here NthPrime(0)=1) */ [[(k+1)*(NthPrime(n)+1): k in [0..n]]: n in [0.. 15]];

Mathematica

Join[{2}, t[n_, k_] := (k + 1) (Prime[n] + 1); Table[t[n, k], {n, 10}, {k, 0, n}] //Flatten]

SageMath

def A289055(n,k): return 2 if n==0 else (k+1)*(nth_prime(n) +1)
flatten([[A289055(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Aug 05 2024

Formula

a(n) = A289108(n) + 1.