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A137823 Numbers occurring in A137822 : first differences of numbers n such that 3 | sum( Catalan(k), k=1..2n). 4
1, 2, 3, 7, 8, 21, 61, 62, 183, 547, 548, 1641, 4921, 4922, 14763, 44287, 44288, 132861, 398581, 398582, 1195743, 3587227, 3587228, 10761681, 32285041, 32285042, 96855123, 290565367, 290565368, 871696101, 2615088301, 2615088302 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This sequence consists of A122983 (which are record values of A137822, i.e. record gaps of A137821), plus the successor of every other term thereof (i.e. A122983(2k+1)+1). See A137822 for more details & formulas.

The (very simple) sequence A137824 gives the index of A137822 at which A137823(n) occurs for the first time.

LINKS

Table of n, a(n) for n=1..32.

PROG

(PARI) A137823(n) = (n%3==2)+3^((n-1)*2\3+1)\4+1

CROSSREFS

Cf. A107755, A122983, A137821-A137824.

Sequence in context: A325105 A276032 A114281 * A024540 A029785 A045545

Adjacent sequences:  A137820 A137821 A137822 * A137824 A137825 A137826

KEYWORD

nonn,easy

AUTHOR

M. F. Hasler, May 15 2008

STATUS

approved

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Last modified May 12 12:34 EDT 2021. Contains 343823 sequences. (Running on oeis4.)