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A037050
Numbers n such that product of n with sum of next n consecutive integers is palindromic.
1
1, 121, 187, 14014
OFFSET
1,2
COMMENTS
Also, number n such that n^2*(3*n+1)/2 is palindromic.
No additional terms below 10^10. - Jens Voß, Feb 20 2009
a(5) > 3.7*10^12, if it exists. - Giovanni Resta, Aug 26 2019
EXAMPLE
187 * (188+189+...+373+374) = 187 * 52547 = palindrome 9826289.
MAPLE
A036659 := proc(n) n^2*(3*n+1)/2 ; end: isA002113 := proc(n) local b10, i ; b10 := convert(n, base, 10) ; for i from 1 to nops(b10)/2 do if op(i, b10) <> op(-i, b10) then RETURN(false) ; fi ; od ; RETURN(true) ; end: for n from 1 to 1000000 do c := A036659(n) : if isA002113(c) then print(n) ; fi ; od : # R. J. Mathar, Jun 26 2007
CROSSREFS
Sequence in context: A074730 A268519 A364778 * A275028 A036309 A346507
KEYWORD
nonn,base,hard,more
AUTHOR
Patrick De Geest, Jan 04 1999
STATUS
approved