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A307492 Numbers that are both centered square and square pyramidal. 1
1, 5, 42925, 1026745 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If it exists, a(5) > 10^29. - Bert Dobbelaere, Apr 12 2019

LINKS

Table of n, a(n) for n=1..4.

Eric Weisstein's World of Mathematics, Centered Square Number

Eric Weisstein's World of Mathematics, Square Pyramidal Number

MATHEMATICA

csQ[n_] := IntegerQ[Sqrt[2*n-1]]; Select[Table[n(n+1)(2n+1)/6, {n, 0, 1000}], csQ] (* Amiram Eldar, Apr 11 2019 *)

CROSSREFS

Intersection of A000330 and A001844.

Cf. A008844, A039596, A131750, A307491.

Sequence in context: A193366 A228547 A193148 * A165711 A167369 A259161

Adjacent sequences:  A307489 A307490 A307491 * A307493 A307494 A307495

KEYWORD

nonn,more

AUTHOR

Ilya Gutkovskiy, Apr 10 2019

STATUS

approved

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Last modified December 5 16:12 EST 2019. Contains 329753 sequences. (Running on oeis4.)