A362072 Antidiagonal sums of A336225.

0, 0, 1, 4, 10, 20, 35, 20, 39, 48, 57, 58, 61, 58, 95, 110, 140, 114, 159, 186, 205, 172, 160, 134, 203, 206, 252, 216, 288, 262, 265, 280, 281, 260, 371, 354, 381, 282, 382, 430, 454, 410, 425, 392, 528, 510, 528, 466, 568, 628, 593, 626, 629, 594, 666, 684, 775

Offset: 0

Author

Stefano Spezia, Apr 08 2023

Keywords

• nonn
• base
• look

Links

• Stefano Spezia, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A003991, A007953, A336225, A353128.

Programs

Mathematica

T[i_, j_]:=Total[IntegerDigits[i*j]]; Table[Sum[T[n-j, j],{j,0,n}],{n,0,56}]

PARI

a(n) = sum(k=1, n, sumdigits(k*(n-k))) \\ Andrew Howroyd, Apr 08 2023

Formula

a(n) = Sum_{k=1..n} A007953(k*(n-k)). - Andrew Howroyd, Apr 08 2023