A168294 Carryless product n times n+1.

0, 2, 6, 2, 0, 0, 2, 6, 2, 90, 110, 132, 156, 172, 190, 110, 132, 156, 172, 280, 420, 462, 406, 442, 480, 420, 462, 406, 442, 670, 930, 992, 956, 912, 970, 930, 992, 956, 912, 260, 640, 622, 606, 682, 660, 640, 622, 606, 682, 50, 550, 552, 556, 552, 550, 550, 552, 556, 552

Offset: 0

Author

David Applegate, Marc LeBrun and N. J. A. Sloane, Jul 06 2010

Keywords

• nonn
• base

Links

• David Applegate, Marc LeBrun and N. J. A. Sloane, Carryless Arithmetic (I): The Mod 10 Version.
• Index entries for sequences related to carryless arithmetic

Crossrefs

Cf. A004520, A059729.

Programs

Python

def A168294(n):
    s, t = [int(d) for d in str(n)], [int(d) for d in str(n+1)]
    l, m = len(s), len(t)
    u = [0]*(l+m-1)
    for i in range(l):
        for j in range(m):
            u[i+j] = (u[i+j] + s[i]*t[j]) % 10
    return int("".join(str(d) for d in u)) # Chai Wah Wu, Jun 30 2020