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A053612 Numbers such that 1+2+3...+a(n) = 1+4+9+...+r^2, for some r. 4
1, 10, 13, 645 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

Joe Roberts, Lure of the Integers, page 245 (entry for 645).

LINKS

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

R. Finkelstein, H. London, On triangular numbers which are sums of consecutive squares, J. Number Theory 4 (1972), 455-462.

EXAMPLE

1^2 + 2^2 + 3^2 + 4^2 + 5^2 = 1 + 2 + 3 + ... + 10, so 10 is in the sequence.

CROSSREFS

Cf. A039596, A053611.

Sequence in context: A164766 A075828 A153584 * A072146 A074674 A241041

Adjacent sequences:  A053609 A053610 A053611 * A053613 A053614 A053615

KEYWORD

fini,full,nonn

AUTHOR

Jud McCranie, Mar 19 2000

STATUS

approved

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Last modified December 12 17:33 EST 2019. Contains 329960 sequences. (Running on oeis4.)