A080464 - OEIS

A080464

Product of the two numbers formed by alternate digits of n.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 0, 6, 12, 18, 24, 30, 36, 42, 48, 54, 0, 7, 14, 21, 28, 35, 42, 49, 56, 63, 0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 0

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OFFSET

10,3

LINKS

M. F. Hasler, Table of n, a(n) for n = 10..10000

FORMULA

a(n) < n for all n. - M. F. Hasler, Jan 10 2016

EXAMPLE

a(132546) = 124 * 356 = 44144.

MATHEMATICA

nad[n_]:=Module[{idn=IntegerDigits[n]}, FromDigits[Take[idn, {1, -1, 2}]] FromDigits[ Take[idn, {2, -1, 2}]]]; Array[nad, 120, 10] (* Harvey P. Dale, Aug 07 2019 *)

PROG

(PARI) A080464(n, d=digits(n))={n=d*matrix(#d, 2, z, s, if((z-s)%2, 10^((#d-z)\2))); n[1]*n[2]}

CROSSREFS

Cf. A007954, A080463, A080465, A087471, A087472, A087473, A087474.

Sequence in context: A088118 A330633 A257850 * A171765 A257297 A035930

Adjacent sequences: A080461 A080462 A080463 * A080465 A080466 A080467

KEYWORD

base,easy,nonn,look

AUTHOR

Amarnath Murthy, Mar 02 2003

EXTENSIONS

More terms from Ray Chandler, Oct 11 2003

STATUS

approved