A118373 Product of decimal digits of two successive natural numbers.

0, 2, 6, 12, 20, 30, 42, 56, 72, 0, 0, 2, 6, 12, 20, 30, 42, 56, 72, 0, 0, 8, 24, 48, 80, 120, 168, 224, 288, 0, 0, 18, 54, 108, 180, 270, 378, 504, 648, 0, 0, 32, 96, 192, 320, 480, 672, 896, 1152, 0, 0, 50, 150, 300, 500, 750, 1050, 1400, 1800, 0, 0, 72, 216, 432, 720

Offset

1,2

Comments

All numbers of the form n(n+1)*k^2, with n>0, are in the sequence.

Links

Table of n, a(n) for n=1..65.

Mathematica

Times@@Flatten[IntegerDigits/@#]&/@Partition[Range[0, 70], 2, 1] (* Harvey P. Dale, Apr 22 2018 *)

Crossrefs

Cf. A002378.

Sequence in context: A034100 A034110 A298010 * A077252 A102069 A160938

Adjacent sequences: A118370 A118371 A118372 * A118374 A118375 A118376

Keyword

base,easy,nonn

Author

Giovanni Teofilatto, May 15 2006

Status

approved