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 A117327 Triangular numbers for which the product of the digits is a heptagonal number. 0
 0, 1, 10, 36, 105, 120, 136, 171, 190, 210, 300, 406, 630, 703, 780, 820, 903, 990, 1035, 1081, 1540, 1711, 1770, 1830, 2016, 2080, 2701, 2850, 3003, 3081, 3160, 3240, 3321, 3403, 3570, 4005, 4095, 4560, 4950, 5050, 5460, 6105, 6670, 6903, 7021, 7140, 7260 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..46. EXAMPLE 136 is in the sequence because (1) it is a triangular number and (2) the product of its digits 1*3*6=18 is a heptagonal number. PROG (PARI) isok(k) = ispolygonal(k, 3) && ispolygonal(vecprod(digits(k)), 7); \\ Michel Marcus, Mar 27 2024 CROSSREFS Cf. A000217, A000566. Sequence in context: A211057 A118415 A051959 * A153371 A248463 A169880 Adjacent sequences: A117324 A117325 A117326 * A117328 A117329 A117330 KEYWORD base,nonn AUTHOR Luc Stevens (lms022(AT)yahoo.com), Apr 26 2006 EXTENSIONS a(24) and a(38) corrected by Georg Fischer, Mar 27 2024 STATUS approved

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Last modified August 9 08:03 EDT 2024. Contains 375034 sequences. (Running on oeis4.)