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A117832 Triangular numbers for which the product of the digits is an octagonal number. 0
0, 1, 10, 105, 120, 190, 210, 300, 406, 595, 630, 703, 780, 820, 903, 990, 1035, 1081, 1540, 1770, 1830, 2016, 2080, 2145, 2415, 2701, 2850, 3003, 3081, 3160, 3240, 3403, 3570, 4005, 4095, 4560, 4950, 5050, 5460, 6105, 6441, 6670, 6903, 7021, 7140, 7260 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..46.

EXAMPLE

595 is in the sequence because (1) it is a triangular number and (2) the product of its digits 5*9*5=225 is a octagonal number.

MATHEMATICA

Select[Accumulate[Range[0, 200]], DigitCount[#, 10, 0]>0||IntegerQ[(1+ Sqrt[ 1+3*Times@@ IntegerDigits[ #]])/3]&] (* Harvey P. Dale, Jul 24 2016 *)

CROSSREFS

Cf. A000217, A000567.

Sequence in context: A110957 A077671 A117833 * A268763 A300850 A210136

Adjacent sequences:  A117829 A117830 A117831 * A117833 A117834 A117835

KEYWORD

base,nonn

AUTHOR

Luc Stevens (lms022(AT)yahoo.com), Apr 30 2006

EXTENSIONS

Corrected by Harvey P. Dale, Jul 24 2016

STATUS

approved

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Last modified April 26 04:04 EDT 2019. Contains 322469 sequences. (Running on oeis4.)