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A224421 The indices of tetrahedral numbers that are also triangular. 2
0, 1, 3, 8, 20, 34 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
E. T. Avanesov, Solution of a problem on figurate numbers (in Russian), Acta Arith. 12 1966/1967 pages 409-420.
EXAMPLE
The eighth tetrahedral number is 120, which is also a triangular number. Hence, 8 belongs to the sequence.
PROG
(PARI) for(n=0, 34, if(ispolygonal(n*(n+1)*(n+2)/6, 3), print1(n", "))) \\ Charles R Greathouse IV, Apr 07 2013
CROSSREFS
Sequence in context: A195676 A027299 A321067 * A354317 A143785 A182735
KEYWORD
nonn,full,fini
AUTHOR
Tanya Khovanova, Apr 06 2013
STATUS
approved

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)