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A073412 Lesser of three consecutive integers each of which is the sum of two squares (zero excluded). 2
72, 232, 520, 584, 800, 808, 1096, 1152, 1312, 1664, 1744, 1800, 1872, 1960, 2248, 2312, 2384, 2592, 2824, 3328, 3392, 3528, 4112, 4176, 4328, 5120, 5408, 5904, 6056, 6120, 6272, 6352, 6408, 6568, 6920, 8080, 8144, 8296, 8352, 8584, 8712, 9160, 9376 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Apparently a(n) == 0 mod 8. - Zak Seidov, Jan 26 2013

Is this sequence the same as A064715? - Zak Seidov, Jan 26 2013

This sequence is distinct from A064715 since it allows numbers equal to twice a square, like 72, 1152, 2592, 3528, etc. - Giovanni Resta, Jan 29 2013

This sequence lists lesser of three consecutive nonsquare integers each of which is the sum of two squares. So this sequence is a subsequence of A064716. - Altug Alkan, Jul 07 2016

LINKS

Table of n, a(n) for n=1..43.

EXAMPLE

232 is here since 232 = 6^2 + 14^2; 233 = 8^2 + 13^2; 234 = 3^2 + 15^2 and 232, 233, 234 are all nonsquares.

288 is not a term because 288 = 12^2 + 12^2, 289 = 8^2 + 15^2, 290 = 1^2 + 17^2 but 289 is also square.

PROG

(PARI) isA001481(n) = my(f=factor(n)); for(i=1, #f[, 1], if(f[i, 2]%2 && f[i, 1]%4==3, return(0))); 1;

isok(n) = isA001481(n) && isA001481(n+1) && isA001481(n+2) && !issquare(n) && !issquare(n+1);

lista(nn) = for(n=1, nn, if(isok(8*n), print1(8*n, ", "))); \\ Altug Alkan, Jul 07 2016

CROSSREFS

Cf. A000404, A001481, A064716.

Sequence in context: A050498 A077535 A064716 * A250749 A019507 A158488

Adjacent sequences:  A073409 A073410 A073411 * A073413 A073414 A073415

KEYWORD

nonn

AUTHOR

Jason Earls (zevi_35711(AT)yahoo.com), Aug 23 2002

STATUS

approved

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Last modified March 30 04:55 EDT 2017. Contains 284296 sequences.