A131700 Sum of all n-digit Cullen numbers.

13, 90, 1443, 6658, 81923, 827395, 17956868, 157286403, 1434451971, 12884901891, 114353504259, 1005022347267, 8761733283843, 166026255794180, 1337006139375619, 11434920928870403, 97390341941886979, 1799188051134513156, 14231374822490767363, 119903836479112085507

Offset

1,1

Links

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

E.W. Weisstein, Cullen Number

Example

Sum of all 1-digit Cullen numbers is 1 + 3 + 9 = 13.
Sum of all 2-digit Cullen numbers is 25 + 65 = 90.
Sum of all 3-digit Cullen numbers is 161 + 385 + 897 = 1443.

Mathematica

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

Crossrefs

Cf. A002064.

Sequence in context: A166215 A296574 A347686 * A156947 A139613 A212956

Adjacent sequences: A131697 A131698 A131699 * A131701 A131702 A131703

Keyword

nonn,base,less

Author

Parthasarathy Nambi, Sep 15 2007

Extensions

More terms from Amiram Eldar, Nov 30 2019

Status

approved