A163744 - OEIS

A163744

Smallest positive m such that A050410(m) = 0 (mod n!).

1, 1, 3, 4, 23, 23, 608, 3703, 59063, 65975, 65975, 65975, 3227648, 83180983

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OFFSET

1,3

COMMENTS

Smallest positive m such that m-th truncated square pyramid number tsp(m)=m*(7*m-1)*(2*m-1)/6 is divisible by n!, n=0,1,.. .

LINKS

EXAMPLE

a(3)=3 because tsp(3)=126 is divisible by 3!: 126/3!=21

a(5)=23 because tsp(23)=27600 is divisible by 5!: 27600/5!=230

a(6)=608 because tsp(608)=523875600 is divisible by 6!: 523875600/6!=727605.

CROSSREFS

Cf. A050410 Truncated square pyramid numbers:a(n)=sum(k^2, k=n..2*n-1)=(1/6)n(7n-1)(2n-1).

KEYWORD

more,nonn

AUTHOR

Zak Seidov, Aug 03 2009

STATUS

approved