This site is supported by donations to The OEIS Foundation.

 Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS"). Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A098839 Smith square numbers. 1
 4, 121, 576, 729, 6084, 10201, 17424, 18496, 36481, 51529, 100489, 124609, 184041, 195364, 410881, 559504, 674041, 695556, 732736, 887364, 896809, 966289, 988036, 1038361, 1190281, 1238769, 1726596, 1852321, 2166784, 2975625, 3407716, 3613801, 3663396 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Donovan Johnson, Table of n, a(n) for n = 1..10000 EXAMPLE a(2) = 121 because 121 is a Smith number as well as a square. MATHEMATICA d[n_]:=IntegerDigits[n]; tr[n_]:=Transpose[FactorInteger[n]]; t={}; Do[If[!PrimeQ[n]&&Total[d[n]]==Total[d@tr[n][[1]]*tr[n][[2]], 2], AppendTo[t, n]], {n, Range[2, 1950]^2}]; t (* Jayanta Basu, Jun 04 2013 *) CROSSREFS Cf. A006753. Sequence in context: A053881 A075114 A017186 * A227525 A071129 A241366 Adjacent sequences:  A098836 A098837 A098838 * A098840 A098841 A098842 KEYWORD base,nonn AUTHOR Shyam Sunder Gupta, Oct 10 2004 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 14 09:49 EST 2018. Contains 318095 sequences. (Running on oeis4.)