A076602 - OEIS

A076602

a(1)=7, a(n_even)=(a(n-1)^2-1)/2; a(n_odd)=a(n-1)+1.

7, 24, 25, 312, 313, 48984, 48985, 1199765112, 1199765113, 719718163185951384, 719718163185951385, 258997117209879873736794713791709112, 258997117209879873736794713791709113, 33539753361514126736178628392779244498735703225085922505721228803623384

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OFFSET

1,1

COMMENTS

{7, 24, 25}, {25, 312, 313}, {313, 48984, 48985}... are sides {a<b<c} of the right triangles, with hypotenuse c=b+1.

LINKS

Table of n, a(n) for n=1..14.

MATHEMATICA

nxt[{a_, b_}]:={a+1, If[OddQ[a], (b^2-1)/2, b+1]}; Transpose[NestList[nxt, {1, 7}, 15]][[2]] (* Harvey P. Dale, Dec 13 2011 *)

CROSSREFS

Sequence in context: A070410 A377011 A077035 * A287132 A287193 A076673

Adjacent sequences: A076599 A076600 A076601 * A076603 A076604 A076605

KEYWORD

easy,nonn

AUTHOR

Zak Seidov, Oct 21 2002

EXTENSIONS

More terms from Harvey P. Dale, Dec 13 2011

STATUS

approved