OFFSET
1,2
COMMENTS
Difference between two consecutive terms is never equal to 8. - Carmine Suriano, Mar 31 2014
In this sequence, there is no number of the form 3*k-1. In other words, if a(n) is not divisible by 9, it must be of the form 3*k+1. - Altug Alkan, Apr 08 2016
LINKS
Carmine Suriano, Table of n, a(n) for n = 1..1242
EXAMPLE
234511 belongs to the sequence as its sum of digits is 16, a square.
MATHEMATICA
Select[ Range[ 500 ], IntegerQ[ Sqrt[ Apply[ Plus, IntegerDigits[ # ] ] ] ]& ]
PROG
(Magma) [n: n in [1..400] | IsSquare(&+Intseq(n))]; // Bruno Berselli, May 26 2011
(PARI) isok(n) = issquare(sumdigits(n)); \\ Michel Marcus, Oct 30 2014
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
EXTENSIONS
More terms from Erich Friedman
STATUS
approved