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A299998 Decimal expansion of Sum_{k>=0} 1/2^(k(k+1)/2). 2
1, 6, 4, 1, 6, 3, 2, 5, 6, 0, 6, 5, 5, 1, 5, 3, 8, 6, 6, 2, 9, 3, 8, 4, 2, 7, 7, 0, 2, 2, 5, 4, 2, 9, 4, 3, 4, 2, 2, 6, 0, 6, 1, 5, 3, 7, 9, 5, 6, 7, 3, 9, 7, 4, 7, 8, 0, 4, 6, 5, 1, 6, 2, 2, 3, 8, 0, 1, 4, 4, 6, 0, 3, 7, 3, 3, 3, 5, 1, 7, 7, 5, 6, 0, 0, 3, 6, 4, 1, 7, 1, 6, 2, 3, 3, 5, 9 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The binary expansion is the characteristic function A010054 of the triangular numbers A000217.

LINKS

Table of n, a(n) for n=1..97.

FORMULA

Equals 1 + A190405 (as a decimal number)

EXAMPLE

1.641632560655153866293842770225429434226061537956739747804651622380144603733...

PROG

(PARI) default(realprecision, 200); suminf(k=0, 2^(-k*(k+1)/2))

CROSSREFS

Cf. A190405.

Sequence in context: A244980 A021863 A259620 * A190405 A180659 A309222

Adjacent sequences:  A299995 A299996 A299997 * A299999 A300000 A300001

KEYWORD

nonn,cons

AUTHOR

M. F. Hasler, Feb 27 2018

STATUS

approved

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Last modified October 21 11:42 EDT 2019. Contains 328296 sequences. (Running on oeis4.)