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A131812 Sum of all n-digit Woodall numbers. 0
8, 86, 1437, 6654, 81917, 827389, 17956860, 157286397, 1434451965, 12884901885, 114353504253, 1005022347261, 8761733283837, 166026255794172, 1337006139375613, 11434920928870397, 97390341941886973, 1799188051134513148, 14231374822490767357, 119903836479112085501 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..20.

Eric Weisstein's World of Mathematics, Woodall Number.

EXAMPLE

Sum of all 1-digit Woodall numbers is 1 + 7 = 8.

Sum of all 2-digit Woodall numbers is 23 + 63 = 86.

Sum of all 3-digit Woodall numbers is 159 + 383 + 895 = 1437.

MATHEMATICA

digNum[n_] := Length @ IntegerDigits[n]; woodall[n_] := n * 2^n - 1; digCount = 0; sum = 0; cumsum = {}; Do[w = woodall[n]; If[digNum[w] > digCount, digCount++; AppendTo[cumsum, sum]]; sum += w, {n, 1, 65}]; Differences[cumsum] (* Amiram Eldar, Nov 30 2019 *)

CROSSREFS

Cf. A003261.

Sequence in context: A268052 A268075 A202545 * A241259 A225314 A200767

Adjacent sequences:  A131809 A131810 A131811 * A131813 A131814 A131815

KEYWORD

nonn,base,less

AUTHOR

Parthasarathy Nambi, Oct 23 2007

EXTENSIONS

More terms from Amiram Eldar, Nov 30 2019

STATUS

approved

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Last modified November 28 23:48 EST 2021. Contains 349415 sequences. (Running on oeis4.)