%I #6 Feb 28 2015 18:32:20
%S 1,7,55,1177,3553,9517,11799,13579,17935,31753,71995,93799,97713,
%T 117397,135373,371911,377719,599515,733597,777573,1131313,1331155,
%U 1371591,1555119,3391315,3731377,3979717,5131573,7137715,7333353,9193933,13755771,13979515
%N Heptagonal numbers with only odd digits.
%t Select[Table[n (5n-3)/2,{n,4000}],AllTrue[IntegerDigits[#],OddQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Feb 28 2015 *)
%Y Cf. A000566, A117994.
%K base,nonn
%O 1,2
%A Luc Stevens (lms022(AT)yahoo.com), May 03 2006
%E Corrected by _Harvey P. Dale_, Feb 28 2015