A113856 Numbers k such that k = (2*d_1 + 1)*(2*d_2 + 1)*...*(2*d_m + 1) where d_1 d_2 ... d_m is the decimal expansion of k.

833, 7425, 17325, 329175, 7194825, 7759125, 275380875, 2256271875, 28879228125, 152156958525, 22342629684375, 2588036347771875, 17452999438621621875, 499296818283476338125, 894477156692665528125

Offset

1,1

Links

Table of n, a(n) for n=1..15.

Example

833 = (2*8 + 1) * (2*3 + 1) * (2*3 + 1) = 17*7*7.

Mathematica

Select[Range[776*10^4], Times@@(2#+1&/@IntegerDigits[#])==#&] (* The program generates the first 6 terms of the sequence. To generate more, increase the Range constant but the program may take a long time to run. *) (* Harvey P. Dale, Jan 12 2022 *)

Crossrefs

Sequence in context: A202773 A095257 A236741 * A245947 A235288 A162945

Adjacent sequences: A113853 A113854 A113855 * A113857 A113858 A113859

Keyword

base,nonn,more

Author

Giovanni Resta, Jan 25 2006

Status

approved