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 A117062 Hexagonal numbers for which the sum of the digits is also a hexagonal number. 1
 0, 1, 6, 15, 231, 276, 780, 861, 1653, 1770, 2850, 3003, 4371, 4560, 5995, 6216, 6441, 11175, 14028, 17205, 17578, 20301, 20706, 24090, 24531, 24976, 28203, 32640, 33153, 36856, 37401, 43071, 47278, 52975, 54946, 56953, 67528, 69751, 76636 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Harvey P. Dale, Table of n, a(n) for n = 0..1000 EXAMPLE 1770 is in the sequence because (1) it is a hexagonal number and (2)the sum of its digits 1+7+7+0=15 is also a hexagonal number. MATHEMATICA Module[{nn=400, hn}, hn=PolygonalNumber[6, Range[0, nn]]; Select[hn, MemberQ[ hn, Total[ IntegerDigits[#]]]&]] (* Harvey P. Dale, Apr 14 2022 *) PROG (PARI) isok(n) = ispolygonal(n, 6) && ispolygonal(sumdigits(n), 6); \\ Michel Marcus, Feb 26 2014 CROSSREFS Cf. A000384. Sequence in context: A013224 A013230 A306342 * A003155 A335578 A199095 Adjacent sequences: A117059 A117060 A117061 * A117063 A117064 A117065 KEYWORD base,nonn AUTHOR Luc Stevens (lms022(AT)yahoo.com), Apr 16 2006 STATUS approved

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Last modified December 1 03:32 EST 2023. Contains 367468 sequences. (Running on oeis4.)